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Dave Pursel

Code versus safe

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There was a couple of responses to a reply I made to a posting that I would like some input from those doing lighting that also have day jobs dealing with electricity. In a recent posting I made the comment that it "doesn't pass code" and "don't try this at home" to a methodology that I'm using during the lighting season. I was told it wouldn't pass code which I already said it wouldn't. And don't try this at home, because if you don't know exactly what your doing there can be safety issues that could result in your house burning down or electrocuting someone, if not yourself. As a result there may be some misconceptions as to what I actually did. The pic I've attached shows that on the left, I have a standard a/c disconnect which is attached with 10-3 w/g to a 220 30amp standard breaker at the se panel. The right side is a twin 15 amp fused disconnect with each fuse (one on each leg) supplying the two circuits and two recepticals that I've tapped into the a/c disconnect. Notice there is a lock attached to each disconnect. This keeps those unfamiliar with things they shouldn't mess with, with messing with those things they shouldn't mess with, if you get my drift. When lighting season is over I simply switch the disconnects (off - on the lighting side - on - on the cooling side). With a safety factor of 20% that means my neutral should never carry more than 28 amps. I'm solicting feedback as to if this is safe or not and why not as even though I've been working with electricity as a non-licensed electrician for 50 years I don't have the day to day knowledge of those of you out there who inspect and do it for a living. I believe this method, which I consider to be temporary wiring, is safer than stringing 300' feet of electrical cords over the ground even though it doesn't pass code. Tx for the comments and insight.

Attached files 293031=16169-IMG_0110-2.JPG

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Hi Dave
I see what you did and I understand why you would do that. It provides you with an easy method to get power for your display which I am sure a lot of people have done.

While your setup is "illegal" in the code sense of the "real world", it appears that you have gone further than most at trying to make it as safe as you can for what you have.
My only comment on this would be that I would have used a transfer style breaker setup for it so that there would be no way to engerize both the ac receptacle and the display receptacles (which is what really makes this illegal by the way, along with the shared neutral).
That said, I admire your setup anyway and see that you have done a much better job at trying to "cover your bases" for safety with this than some of the absolutely scary things that I have seen over the years.
This is something that you own, monitor, and operate, so I don't see a real problem here other than maybe a fulltime weatherproof note near the disconnects stating that only 1 shall be "ON" at a time since you can't tell which is on without opening them. That way if something should happen to you, then whoever opens them will know.

You are smart enough to figure your shared neutral out and obviously know what you are doing with this so I wouldn't worry.
But I would not recommend telling a lot of people about it either since it is dangerous and so many folks are getting into the display lighting that have no clue about electricity and the dangers of it.
Maybe tell them that a transfer style setup would be more appropriate for them as it is safer. You already have yours in place so changing it does not make much sense at this point.
Otherwise leave it there and enjoy your lights! You stated that it was dangerous and not to try it at home. You were only giving people "options" in my eye and nothing wrong with that at all. We are all here to learn new things and teach each other.
Some folks will react to things without actually "getting it" and that can cause misunderstandings sometimes.
Don't let it bother you and enjoy the fruits of your labors for the holiday season.

Bill

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Its a whole lot safer looking then the quarter mile of extentions cords I have coming from the controllers. I have someone coming out in spring to do some work on the townhouse for me in a few hidden areas to make it better in terms of wiring having a common shutoff like you do so that those sockets are powered only during season.

Im nowhere near smart enough to play with power in that capacity. I do play with it in terms of a ceiling fan or a dimmer switch, but pulling a 220 down to 110 is beyond me. As for doing what you did to make it as safe as possible for what you can do I give you props for that. I would have a bunch of wires pulled straight from the transformer next to my house if I knew how I wouldnt die. The neighbors, some I wouldnt miss so much.

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I use a 220 50 AMP rv plug which through out the rest of the year my camper runs off of. It runs to a portable breaker box in my display which then breaks the 220 down to 110.

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Dave

I am an electrical inspector. I can not see inside the equipment, but as you describe this set up, I see no code violations. If I were to open the outlet covers - I would see GFCI's-correct?

Steve

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beeiilll wrote:

Hi Dave
(which is what really makes this illegal by the way, along with the shared neutral).

Bill

Can you help me out with this............why would a shared neutral be illegal?

I think it's a legal thing to do.

I do agree, If you don't know what to do, stay away from making changes to an electrical installation. Ask for help from a professional. But the electric code does allow alterations to a system.

Steve

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The power circuit for an air conditioning unit is a dedicated circuit. It is legal to tap off of an air conditioning circuit as long as the supply circuit is rated at 115% of the sum of all loads. The intention of this provision isn't necessarily for Christmas lights, but rather for other HVAC related equipment, however it doesn't specifically exclude other loads. At least where I look in the code book.

In other words, if your air conditioner is 50A and your other load(s) is 40A, then the circuit must be rated for 90A plus the 15% over, which would be 103.5A (Rounded up to 110A). Ref. NEC 440-12(B)(2) I would wager that there isn't anyone will the capacity to meet the code requirement on their A/C circuit. You will still need to provide GFI protection for the lighting circuits.

Here is where someone can get into trouble; heat pumps. A heat pump runs the outside unit whether you are using heat or cooling inside. There are a lot of folks out there that have no clue what their system is. If they tie into the A/C circuit, then they will overload the circuit and create a lot of tripping events.

A lot of people's solution to the tripping of a breaker is buying a higher rated breaker and replacing the existing breaker thinking they are saving themselves a lot of trouble. In this case a dangerous situation has been created and the risk of destroying your heating & cooling equipment is high, not to mention you have a pretty high risk of meeting your local fire department.

Another pitfall; inrush currents when an A/C starts up can also create problems for our LOR controllers. There is a voltage drop when a motor starts because of the spike in current until the motor starts. As the voltage decreases, current increases in a load. For electronics, this condition isn't healthy and can result in the magic smoke departing the electronics.


Dave, while you put over-current protection (breakers) into your set up, it still isn't a best practice to tap off of the air conditioning circuit for the above reasons. Many folks wouldn't think ahead and go as far as you did (or spend the money), so there is another reason not to plant this seed in people's minds. Too many variables and too much room for error!

No harm; no foul. Just not a good practice. And has been stated, DON"T DO THIS AT HOME!!



By the way, the neutral only carries the unbalanced load. Your circuit feeding your sub-panel is 50A and the wire size is number 8AWG, then make sure the neutral is number 8AWG as well, and you'll be safe. If phase A is drawing 25A and phase B is drawing 35A, the load on the neutral will be 10A which is the unbalanced load, not 60A.

Where you can get into trouble on a neutral is by stacking multiples of the same phase on a neutral conductor. For instance, you have three channels serving a display item, and only four wires going out; three hot/phase wires (same supply circuit), and one neutral. The loads stack up on the neutral and can burn it up.

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Love the feedback. I've been in the OLD code book many, many times and it's always fun, sometimes, trying to intrepret what's legal and what's not. By the way I did think about installing a DPST type of "transfer switch" versus a "hand switch" to keep it legal, but I want to spend my money on more lights of course ..... : ) Another type of important consideration. What happens if I get kissed by a mac truck. Is my wife or the next family that buys my house going to understand what I've put on the wall outside. De Trommelslager response is probably one of the primary reasons why I posted this. To learn and teach. Having been in the education field I always feel like I'm trying to educate others even though I wasn't a teacher. But the old proverb "a little knowledge can be dangerous" sure holds true. In todays world everyone relies on the internet (forums) to solve questions and learn. It gives us all a way to learn. Thank you for contributing De Trommelslager. I said a/c disconnect in my original post. Heat pump systems are a/c systems and even though I had condensers in mind, heat pumps are going to operate year round. Many more electrons are flowing at the same time as a result. His response lets us know, that you need to KNOW how your using the electricity and MORE IMPORTANTLY, HOW MUCH electricity your using. Because ALL of us utilizing these lighting systems have to be cognizant of how much electricity/current we're utilizing and how it's making the lights blinky blink. The controllers have limits as to how much current they can carry. You can't just buy a controller and a bunch of lights and start pluggin in lights and cords without understanding electricity. For all of the newbies out there, you really should study the abc's of electricity. Ask yourself questions like these. What is electricity. Why does that installed circuit breaker have a 15, 20, 40 or 50 marking on it. Why can't I use 16 gauge wire instead of 12 or 14 gauge wire. Why do I have to use one of those damned GFCI's that keep tripping when it's raining out. Of course what we read has to be understandable. Just for the record, I know electricians that don't have all the answers. That's how complex electricity/code can be at times. A few years ago I found it disturbing to watch a house burn down across the lake. The image of the owners trying to salvage their pictures on their lawn the next day is an image I'll never forget. It was an electrical fire. Food for thought. Ask questions if in doubt. You'll enjoy your Christmas lights more when their lit. Disclaimer. How you use and what you do with electricity is YOUR responsibility! And no matter what the excuse is, never substitute a higher capacity breaker for a lower one. Never use a penny behind a fuse. Never use 16 gauge wire where 14 gauge is required, etc.........

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Sorry I forgot to answer some questions. Questions/comments: rescue_653 Use of a 50amp rv plug. I have an outdoor 50amp "welder" receptical that I never use for my generator. Unfortunately it's on the other side of the house. Might as well be in the back 40. Otherwise I would have done the same thing as you. Not knowing how you've wired that "breaker" box could be a concern. A 50 amp breaker in your se panel won't blow at 40 amps and if your using 12 or 14 ga wire between the rv plug and your breaker box, you could very easy overload the wiring between the two. I'll assume you know that. Just commenting for others that may read this. Steve. Correct. Those 4 recep boxes have GFCI's. But after last night I may be mounting those boxes 6' 7" up the side of the house. That way I wouldn't violate 210-8-a-3. Outdoor recepticals must be have a GFCI. They need to invent a self resetting GFCI. Say, maybe, resets after 5 minutes. Because at that point you will have already been dead and it won't matter if it resets!...... : ) And I only say this because as a result of all the trips I just started having this year (unlike previous years, I've been studying at what milliamps the body goes into clamping and when you can't let go, which depends on male vs female, how well grounded you are, etc, and makes me wonder if the leakage that's causing my trips is exceeding 9 milliamps such that a more tolerant GFCI (which are typically 4-6 milliamp inbalance) would help us all and still provide protection against electrocution. Whom I lost not one, but two school mates too. Yes I've seen a lot. And I respect electricity a lot as a result. In the case of the shared neutral Steve, mine is balanced. Sine waves, can't live with them and can't live without them. But as De Trommelslager points out their are a lot of electrical newbies out there that don't know their abc's. If they were somehow taping into two seperately protected ungrounded conductors off the same leg thus causing an unbalanced neutral, that neutral would be carrying twice the load possibly causing the neutral to go up in smoke as a result. So to answer your question the code thing I believe I'm violating here is the uncontrolled "switching" that De Trommelslager was also wondering about and possibly violating may/is covered in 210-10 (manually switched TOGETHER) of 1990NEC.

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steve synek wrote:

beeiilll wrote:
Hi Dave
 (which is what really makes this illegal by the way, along with the shared neutral).

Bill

Can you help me out with this............why would a shared neutral be illegal?

I think it's a legal thing to do.

I do agree, If you don't know what to do, stay away from making changes to an electrical installation.  Ask for help from a professional. But the electric code does allow alterations to a system.

Steve


Hey Steve

Well I am not 100% on the NEC book all the time, but I use an Underwriters Inspector that would crucify me if I ever used shared neutrals in a residential home wiring.
He has told me that it is absolutely illegal in residential wiring to do so I go by his word.
Of course the UL inspection is a much tougher inspection to pass than a regular standard NEC type electrical inspection (at least here in NY).
My UL inspector spends at least an hour or more on a final and has at least a half a dozen outlets pulled to check as well as he really inspects a panel box and all feeds, GFI's, GFCI's, wire sizing, - basically everything and anything that is electrical.
I personally like it (even though I do have failures on inspections occasionally) and it keeps me sharp on being careful and doing a top class job rather than just slapping in things.
Of course the UL also frowns on step down wire sizing as in tapping a 14-2 light circuit off a 12-2 receptacle circuit even though the standard electrical inspector will allow that as well.

I would rather be safe than sorry.

Bill

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beeiilll wrote:

Hey Steve

Well I am not 100% on the NEC book all the time, but I use an Underwriters Inspector that would crucify me if I ever used shared neutrals in a residential home wiring.
He has told me that it is absolutely illegal in residential wiring to do so I go by his word.

Of course, any state can pass legislation requiring more than NEC. But the key thing here is that this is not necessarily what one thinks of when you say shared neutral. This is a 220V circuit with neutral to support 220 or 110V loads. It must be on a 220V breaker, and the neutral must be sized the same as the hots. So this is a single neutral, supporting a single breaker. The fact that it may have a load panel at the end feeding more breakers, or a pair of 110V outlets does not change that it is a single circuit off the load center.

But yes, one could state no shared neutrals, in that every neutral shall have only one breaker required to completely deengergize all loads on that neutral. Which is a statement that does not in any way contradict what I said above.

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I have a question: It appears from you picture that you have increased the distance from the SE to the a/c disconnect by almost a foot. Did you have to pull new wires, or was there already that much slack in the existing wires?

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There is another statement in the NEC that really nullifies (in a certain sense) everything in it. However, it is important to know and that is in Article 90.4.

"The authority having juristiction (your electrical inspector) for enforcement of the code (NEC & local codes)has the resposibility for making interpretations of the rules, for deciding on the approval of equipment and materials, and for granting the special permission contemplated in a number of the rules."

What this means is the final word falls on the shoulders of the electrical inspector having juristiction. If an electrical inspector doesn't like what they see, then you will be fixing the problem, whether you are right or wrong in what you have done. Work with them rather than fight them; you'll be much better off in the long run and may even learn something.

Now, as with every profession, there are inspectors out there that don't have any business inspecting electrical installations. Over the years, I have had to deal several that didn't know the differenve between AC and DC, let alone the systems that were were working with. That is an exercise in patience, but be polite and work with them. With a good attitude, everyone wins.

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Regarding Dave's response on electricians and even them not understanding electricity fully, he is absolutely correct. There is so much to the science of electricity, and new things are constantly being discovered.

If you want to really throw some curve balls at an electrician, ask one to explain harmonics to you. Or study up on grounding and ask them questions. Most electricians that I have worked with do not have a solid understanding of grounding, yet it is one of the most important aspects of building safe power systems.

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beeiilll wrote:

steve synek wrote:
beeiilll wrote:
Hi Dave
(which is what really makes this illegal by the way, along with the shared neutral).

Bill

Can you help me out with this............why would a shared neutral be illegal?

I think it's a legal thing to do.

I do agree, If you don't know what to do, stay away from making changes to an electrical installation. Ask for help from a professional. But the electric code does allow alterations to a system.

Steve


Hey Steve

Well I am not 100% on the NEC book all the time, but I use an Underwriters Inspector that would crucify me if I ever used shared neutrals in a residential home wiring.
He has told me that it is absolutely illegal in residential wiring to do so I go by his word.
Of course the UL inspection is a much tougher inspection to pass than a regular standard NEC type electrical inspection (at least here in NY).
My UL inspector spends at least an hour or more on a final and has at least a half a dozen outlets pulled to check as well as he really inspects a panel box and all feeds, GFI's, GFCI's, wire sizing, - basically everything and anything that is electrical.
I personally like it (even though I do have failures on inspections occasionally) and it keeps me sharp on being careful and doing a top class job rather than just slapping in things.
Of course the UL also frowns on step down wire sizing as in tapping a 14-2 light circuit off a 12-2 receptacle circuit even though the standard electrical inspector will allow that as well.

I would rather be safe than sorry.

Bill


I also like this open discussion on one of my favorite topics.......electric code....


Bill

Thanks for the response. Here in Ohio, generally speaking, the electrical inspector is the only one doing an inspection on new residential wiring. Ohio has adopted the 2008 NEC as code without any amendments. You mentioned both an Underwriter Inspector and a UL inspector. In my mind, those are two completely different groups-and two different backgrounds-and are not NEC code inspectors. Are 3 groups requiring electrical inspections in NY? I would like to hear code sections for disallowing shared neutrals (multi wire branch or feeders) or not allowing combinations of#12 and #14 wire on a 15 amp circuit.

As an overview to everyone...........don't be afraid to ask that inspector for a code section. This inspector respects everyone who asks for that information so much more that the guy who says "just tell me what you want". I don't want anything. My job is to make sure it complies with the minimum standards required by the NEC.

As an overview of this specific installation, I did make some assumptions. (You know what they say when you assume). I have a hard time leaving Ohio and forget that everyone doesn't live in this state when communicating here. We only have about 3 months of AC season. I should have asked Dave where he lives. This is an AC disconnect and not a heat pump. There is no code requirement here to have AC and as such, lets disconnect the AC and call this a multi wire feeder and branch circuit for Christmas lights from Oct to Feb. Proper size over current protection-two pole, insulated grounded conductor(white), gfci protection at the outlets. Code compliant.

Steven..................are you asking where there might be a splice in the feed to the original AC disconnect?? What kind of wire stretcher did Dave use? What are the specifics on how both disconnects are fed? Is there a junction box just inside the house with a Y connection? one to each disconnect? Is there any double lugging in the first disconnect daisy chaining to the 2nd disconnect ? Is there any illegal splicing in the raceways?

De Trommelslager- don't ask this inspector anything about DC, control wiring or harmonics........I know nothing!!!!! (total knowledge about harmonics- run one neutral per hot leg and worry less).


Steve

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Something I never said is that I wired my own home under the 1975 Nec. I think it was Steve that wanted to know how I made it to the disconnect from the se panel. I have a really good wire stretcher that will add a couple of feet onto a 20' run with no damage what so ever. I sell them really cheap. My attempt at humor. To answer your question as to how I stretched the wire, as luck would have it, I just had to pull it back about 10' and redrill and reroute to get me the extra foot or so I needed. And because I'm not being paid, nor on the clock, my workmanship is better than most electrical contractors I've seen. There would be no sense in rewiring the ac circuit for a foot of wire. Personally, I would have ran a couple of new circuits if I had to rewire back to the panel. Copper is not that expensive yet. And this is not a permanent installation - just temporary. A question for you guys. The following comments were made in your post -
1. "Of course the UL also frowns on step down wire sizing as in tapping a 14-2 light circuit off a 12-2 receptacle circuit even though the standard electrical inspector will allow that as well"
2. "not allowing combinations of#12 and #14 wire on a 15 amp circuit"
If I was an inspector "power to the inspectors", I would deny a #14 tap to a #12 based on 210-19 refering to "not less than the maximum load to be served". Because if a breaker has #12 at the se panel than the maximum load capacity that COULD be served is 20amp even though a 15amp breaker is limiting the maximum load that COULD be served. If that's the case, I wouldn't allow a #14 tap in case someone did decide to change the breaker just because they see it has 12 ga wire at the breaker.


UL? NEC? My 1602 LOR controller enclosure is UL listed but not my CTB16PC's. Does this mean I can't use them in NY.......... I have a feeling I'm glad I don't live in NY. There is absolutely no reason there should be two Code entities in the U.S. It's either residential or commercial. Too much time, money, and productivity is wasted otherwise.


A couple of other questions was in your minds. Double lugging. Not legal. Illegal splicing in puller boxes. Not legal. Sometimes we cheat a little when we have temporary wiring. I may have violated that pouller box one for a couple of days because my wire stretcher wasn't working and had to make do until some longer pieces were obtained. Remember I didn't say it was code compliant. Just safe.

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PS. Here, Here to De Trommelslager mention of grounding. If a breaker doesn't trip what good is it. Thanks for the responses guys, I have to go and find some tubes and knobs now. Hoepfully their under the bed covers.

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Dave Pursel wrote:

PS. Here, Here to De Trommelslager mention of grounding. If a breaker doesn't trip what good is it.


In older appliances, and even some modern home shop equipment, or even some modern appliances with metal cases, good grounding is what causes the breaker to trip, instead of the case being electrically hot in some types of equipment failure.

But there are decidedly a range of less than clear issues about grounding be it the actual method of tying to earth, or tying circuits back to the panel.

Heck, some unusual circumstances are clear as mud as well. For example, a 200A panel mounted on a rural service delivery pole. Then two or more buildings are fed from that 200A panel via underground conduit or direct burial cable.

Is ground tied to neutral in this pole panel, and both service entry panels?

Do both service entry panels and the pole panel get their own earth ground?

Do ground wires run between the panel on the pole, and and the service entry panels?

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Is this a test? ;)

A fault current has to get back to the source in order for the breaker (or fuse) to trip. A grounding system (ground wires, structural steel, etc.) is what facilitates that. If there is enough resistance in the fault path back to the source, the breaker won't trip and bad things happen.

-klb- wrote:

But there are decidedly a range of less than clear issues about grounding be it the actual method of tying to earth, or tying circuits back to the panel.

Heck, some unusual circumstances are clear as mud as well. For example, a 200A panel mounted on a rural service delivery pole. Then two or more buildings are fed from that 200A panel via underground conduit or direct burial cable.

Is ground tied to neutral in this pole panel, and both service entry panels? 


Yes. A ground is bonded to neutral at the first point of service. The panels in the two buildings could be treated as sub-panels, however they are considered as the first point of service for the structure and are required to be bonded (neutral & ground).

-klb- wrote:

Do both service entry panels and the pole panel get their own earth ground?


Yes. The service entry must be bonded to Earth ground (grounding electrode, or driven ground rod). Other requirements also apply (grounding to building steel, etc.)

-klb- wrote:

Do ground wires run between the panel on the pole, and and the service entry panels?


Yes. Earth ground has enough resistance that a fault current may not trip the feeder breaker.

There are some exceptions, but as described each panel would be bonded (neutral & ground) and grounded (grounding electrode).

Lots of twists and turns when it comes to grounding! And this is a simple scenario. :shock:


This seems to be going off topic, but it is still relevent to having a safe power system. For those that don't understand grounding, this all might be overwhelming. If you are unsure, seek help from a qualified electrician. An improperly grounded power system is very dangerous!

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Great discussion on the electrical topic here.

Steve synek:

I should have been clearer in my post on Underwriters and UL as they are one and the same. An Underwriters inspector will give the job a UL listing which just means a better "quality" of workmanship and adherance to codes above a regular electrical inspection based on the NEC codes.

Please don't anyone jump on me for that statement but I have found that as Dr Trommelslager noted:
"Now, as with every profession, there are inspectors out there that don't have any business inspecting electrical installations".
I too have found a few inspectors that will do the NEC based inspections and just want their money more than wanting to look (and some don't even look) at the job. I will not accept that as it is my name on the job and I take a lot of pride in my work and I want it to be correct as well as safe as possible for the owner.

I find that an Underwriters (or UL) inspector is much more thorough with inspections and will help me better understand any changes to codes that come out.
I am the type that I can read things and they don't "hit me" or I don't understand them right away (I am also slightly dislexic which makes reading tough), but I can look at things or get "hands on" and fix most anything that I tackle.
I am an old time "jack of all trades" if you will as I do elecrical, plumbing, heating, and carpentry. This is somewhat out of a need to survive where I live since the nearest real town is over an hour away.
But I am very stubborn on following the codes and doing things right (which is a headache to some of the other contractors around here who will shortcut stuff to make a quick buck and run or worst those who try to take advantage of the wealthy landowners who have property here and need little things done).
So that is why I use the Underwriters as they are not afraid to help me and more often than not they are more up to date on the NEC. I do "trust" the inspector to make sure that I am doing the right thing and that it will pass any code scrutiny from anyone.

Dave:
You stated:
If I was an inspector "power to the inspectors", I would deny a #14 tap to a #12 based on 210-19 refering to "not less than the maximum load to be served". Because if a breaker has #12 at the se panel than the maximum load capacity that COULD be served is 20amp even though a 15amp breaker is limiting the maximum load that COULD be served. If that's the case, I wouldn't allow a #14 tap in case someone did decide to change the breaker just because they see it has 12 ga wire at the breaker.

That was my point by my statement in my other post.

A regular inspector will let this go by (partly because most of them do not take the time to really inspect jobs) whereas my Underwriter inspector would catch something like this and fail me.
I would rather fail than let it go and I do know many electricians around here who will do this routinely as a matter of their work. It is a dangerous practice but they all seem to get away with it.
I have come upon places where a light was tapped off a 30 amp 220 dryer circuit and the panel box was only 6 feet away! How scary is that?

Common sense has always seemed to be the best with me on most anything.
If something seems wrong, then it probably is!

And this quote:

"This seems to be going off topic, but it is still relevent to having a safe power system. For those that don't understand grounding, this all might be overwhelming. If you are unsure, seek help from a qualified electrician. An improperly grounded power system is very dangerous!"

This couldn't be more true except it can be tough to find a "qualified electrician" at times. With the economy being what it is there are many people out there who are doing whatever they can to survive and will take on things that they should not do.
Human nature being what it is, people are also many times too proud to ask for help or clairification on something if they are not sure and will just go ahead even if it is wrong.
I love inspectors personally as they are my best friends at making sure things are right and I use them constantly as they are the ones who know the real basics of the trade and how things need to be done correctly.

I went to a house yesterday to look at a GFI receptacle not working. The line and load sides were reversed as well as the hot and neutral lines were reversed too!
This was installed by a "qualified electrican" when the house was remodeled a couple of years ago and passed inspection by a regular inspector!
It has never worked so I wonder how the inspector got the GFI to trip if he "really" inspected it?
I also found on a basic inspection on the panel box that the electric water heater had the 220 wires hooked to the DP breaker but the ground line was not hooked up! The water heater sits next to a washer dryer combination and a meter showed 220 when connected between the heater case and the washer case!!!
Nothing like having a booby trap set up. Luckly the heater is back in a closet where someone could not reach in and touch it because the washer is in the way. I found it because I crawled into the other side to test and see. Again another qualified electrician job?
The workmanship in the world today scares the crap out of me and the things that people will let go can be deadly if they don't use their head.

Oh finally. Dave you can use your controllers up here in NY - LOL.
There really is only the NEC if you come down to it, but I will waste time, money, and productivity if it means that my work is safe and correct. I live in the sticks and people around here are very much the "don't worry about it" attititude and laid back.
That is fine for them and just wonderful till somebody gets hurt or killed.
I am proud of my own perseverance and workmanship skills to say that it will not happen on my jobs if I can help it!

Check twice - do once! It really is pretty simple to be safe and right.

Merry Christmas all!
Bill

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I agree that you can find quite a bit done wrong by qualified electrical contractors. The city park has a 400A panel, in an outdoor enclosure, with conduit to 7 different locations through the park, and seasonal use outlet panels that go with them, and a total of 36 20A GFCI outlets, each on their own circuit. This was done 3 years ago, for about $30,000. I spent quite a bit of time over the first two years identifying and complaining about significant safety issues, and getting the contractor to fix them.

This year, we were still finding more issues with their original work, and fixing them on our own.

But, even scarier is the stuff done 5 years ago, on the back of the fire station. Also by a licensed electrician. We are continuing to improve that as well.

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I really enjoy threads like this. I do not have the expertise that some of you have and learn something from these threads. I am always referring to NFPA 70 and NFPA 70E at work to make sure things are being done correctly.

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How does the shared neutral work with the GFCI? It looks to be like you have 2 different hots on a shared neutral. If one controller dims or the load changes why does it not trip the gfci? Thanks Chris

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If you are doing something like putting a sub panel, like a hot tub panel on 220V GFCI breaker, it is a single 220V circuit with neutral. The 220V GFCI has connections for both hots, and also passes neutral through the breaker, just like a 110V GFCI passes neutral through the breaker. Then the hot tub panel may have multiple breakers, at 220V, and 110V.

Or, if you are using GFCI outlets, again, as a sub panel off the 220V circuit, the GFCI protection only extends from the GFCI outlet onward. So again, the 220V circuit with neutral, which allows it to support 110V loads, is not a problem with GFCI..

And again, these cases are not shared neutral, as the neutral is only serving one breaker, thus one circuit.

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Chris B wrote:

How does the shared neutral work with the GFCI? It looks to be like you have 2 different hots on a shared neutral. If one controller dims or the load changes why does it not trip the gfci? Thanks     Chris


Here is a picture that shows what is heppening in the GFI and how they can be wired with a common neutral.

66e49c8f.jpg

In the image, the neutral wires (gray in this picture) are tied together. The neutral only carries the unbalanced load. So, if the black phase had 13A and the red phase had 12A, the neutral would only carry 1A - the unbalanced load. Logic would dictate otherwise and it would appear that the load on the neutral would be 25A.

Where one can get into trouble: if both of the wires feeding these two receptacles were on the same phase, then the neutral would carry the sum of both receptacle's loads because there isn't a phase to balance to. Both phase wires (if on the same phase) are on the same plane.


To answer your question, the GFI doesn't care how much current is being drawn by the load; that is the circuit breaker's job. The GFI is just making sure that what is going out is coming back, and if not it opens the circuit.

A GFI works by comparing the current on the hot and neutral. If there is an unbalance of 4-6mA (.004A-.006A), then the GFI opens the circuit to stop the flow of current. And that isn't a lot of current!



Reality check...

Before ditching the GFIs (not saying anyone is here, just a blanket statement), take a moment to think about their importance to what we are doing. We light our homes for people to enjoy. Those blinky lights will bring "Curious George" into your yard sooner or later, and "George" will have to touch something. If that something had a voltage potential and George closed the circuit, in could mean a tripped GFI, or an obituary. And that obit would certainly take the joy out of the lights!


Some quick numbers; the typical human male starts to feel a shock at 5.2mA-6.2mA (.0052A - .0062A). The threshold of muscles not being able to let go is between 16mA-20mA (.016A - .020A). That single 125V 15A circuit can deliver 1,000 times enough current to kill a person!

That's why GFIs are so important.



Chris, hopefully that answers your question.

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