Came home to a tripped circuit breaker :-(

[lowepg]

So the show has been running for 3 days without a problem...

Came home tonight to half the lights out during the post-show.

I guess since it ran for a few days I ASSumed I was in the clear re: power..... I guess I guessed wrong!

I had a new GFCI line and breaker put in before halloween (20A) that runs one side of the house and the other is a 15A breaker that was already there. The 15A tripped.

The 15A circuit is running:
2 singing faces (approx. 8 100-ct mini lights each)
3 arches (approx 7 strings of mini lights each)
10 mini trees (approx 6 strings of mini-lights each)
3 strings of icicle lights
3 flood lights (1 75W incan, 2 8W LEDS)

Guess I need to pull out the Kill-A-Watt tomorrow and measure everything :-)

Im HOPING I have some capacity on the new 20A circuit to shift some stuff over to it....

[need lights]

Is that 15 Amp circuit dedicated to just your display or is it shared with something in the house? Assuming you had a full 120 Volts at your house (electrical panel) the 15 Amp breaker will trip as you approach 1800 Watts (1725 Watts if you only have 115 Volts). As a good rule of thumb you should try to only load a circuit to 80% of the maximum rating (15 Amps in your case) which would be 12 Amps or 1440 Watts (at 120 volts). You should be able to add up what each of your strands draws for wattage and save yourself from needing an ohm meter. On the 20 Amp circuit, at 120 Volts, the breaker will trip as you approach 2400 Watts, and 80% would be 16 Amps or 1920 Watts. Just remember that any current leakage during rain is accumulative, so even though you may not have tripped a GFCI in the past, if you add more load to it you may create a future issue when it rains. I personally use two separate GFCI outlets for each controller fed from one circuit, as I run LED so do not come anywhere near the circuit capacity. I have had a GFCI trip in the rain when the controller was using one GFCI for all 16 channels.

I am a Master Electrician so to me it seems simple enough to just add another dedicated circuit with a couple of GFCI outlets for your show, but hopefully the info I gave you helps you with finding a quick solution. Good luck.

[lowepg]

Yikes... just did some detective work with my Kill-A-Watt

There are 4 controllers on that circuit:

Controller #1
5 x 4' Mini-trees
Each mini-tree is comprised of about 6 strands of incan mini lights (red, green & clear)
with all circuits on:
91Volts
19A
1809W

Controller #2 (identical load for #1 )
5 mini trees
101V
22.48A !!!!
2287 Watts

Controller #3
2 Holiday Coro singing faces (so about 18 total 100-ct strings)
4.9A

Controller #4
3 arches
2 flood lights
3 sets of icicles
4.9A

Now, those readings are with all channels lit, which is atypical, but I was a bit shocked at those Amperages?!?!!?

[Tim Fischer]

The "91 volts" is way out of spec.  How/where are you measuring that?  Should normally fall between 110-125V.  I

[lowepg]

The "91 volts" is way out of spec.  How/where are you measuring that?  Should normally fall between 110-125V.  I

 

Just taking the 3 readings from the Kill-A-Watt device....

[Tim Fischer]

Just taking the 3 readings from the Kill-A-Watt device....

Sorry I should have been more clear.  Where are you plugging in the Kill-A-Watt?  Right into the outlet?  At the end of your light string? 

I've you're pulling that kind of load over a long distance and underrated extension cord, I could maybe see that sort of voltage drop (it would be somewhat concerning though), but if you're seeing that right out of an outlet, that would be even more concerning.

[lowepg]

Sorry I should have been more clear.  Where are you plugging in the Kill-A-Watt?  Right into the outlet?  At the end of your light string? 

I've you're pulling that kind of load over a long distance and underrated extension cord, I could maybe see that sort of voltage drop (it would be somewhat concerning though), but if you're seeing that right out of an outlet, that would be even more concerning.

 

Sorry, I misunderstood your question:

I plugged in the K-A-W right at the controller- yes- both those are at the end of a long run of extension cord, split several times along the way

[Tim Fischer]

Sorry, I misunderstood your question:

I plugged in the K-A-W right at the controller- yes- both those are at the end of a long run of extension cord, split several times along the way

That's a crazy amount of voltage drop.  I'm guessing you're overloading some extension cords to a fire-hazard level.  I hope I'm wrong

[Tim Fischer]

and that's when the neighbors knock on your door because their house lights are blinking with yours.

That's not really your problem though, is it?  It's the power company's job to provide them with a clean power feed.  It's up to me to do whatever I need with mine

[lowepg]

That's a crazy amount of voltage drop.  I'm guessing you're overloading some extension cords to a fire-hazard level.  I hope I'm wrong

 

So.... upsize the extension cords and run the controllers back to the receptical directly (vs daisychainng them)?

 

It's been a while since college EE principles, but if P=IV, than the lower Voltage I've been supplying the lights would require more Amps to meet the Power required? So, potentially I can drop the current draw by addressing the voltage drop?

[dgrant]

I created two additional 15 amp circuits just for my light controllers. I'm probably %95 LED's so there's very little issue with overloading. My show did die on me two nights ago though and it was an electrical failure that happened. On those two added circuits, one of them, the return(neutral) line feed, came out of the wire nut, which the imbalance tripped the GFCI. At the time, I thought it was all the ice outside from the storm but it wasn't the case. Thought I had the wire nuts inside the junction box all nice and tight but apparently not the case.

 

If your CB box is full, there are available, 15 or 20 amp breakers, that are half-sized, therefore two individual 15's or 20's on one slot as opposed to just one. Using some 12/2 or 14/2 romex from there to the wall location, then wire it up. If you aren't good with electrical or not sure in the slightest, hire this all out to a formal electrician. Remember that anything going outside, needs GFCI protection. Here, even in my inside garage, GFCI is mandatory.

[need lights]

Not all circuit breaker panels are rated for those tandem breakers ("half-size breakers"). There is a diagram on the electrical breaker panel, inside the door, where the manufacturer's name is. It will show a line across each slot. It will show two lines across one slot to indicate where you can safely use those tandem breakers. Some panels are specified for all of the circuits, some for just some on the bottom of the panel bus, and some none at all (if you have a 40 circuit panel it is definitely not rated for them). If you are not sure, call a licensed pro. Sometimes you need to add a sub panel or larger panel depending on your existing conditions.

The voltages you have listed are a problem if those values are in fact correct. If it is voltage drop because of the length of your runs, you would find the proper voltage at the point of origin. If at that originating outlet it is still low you need to check the voltage at your electrical panel. You will have two phases (hot legs) coming in from your utility meter. They should be close to 110-120V. I would call the power company if either hot leg is lower. As you may know, with those lower voltages your lights aren't as bright as they could be and if you have voltage drop problems in your house you could be damaging equipment, motors, etc.

What guage cords are you using and how long are they in total length?

[dgrant]

I didn't know about the CB markings so will look at mine just in case and Thank You for letting us know about that. Always best to hire an electrician to be sure. When I had my pool put in last year, I ended up teaching the electricans how to connect the computerized control panel and I paid for it!

[dgrant]

Yes, I checked my CB box and I'm good. All locations are dual position capable. Again, thank's for letting us know about that.

[lowepg]

OK- some new data (now that its light outside)

 

Embarrassingly, I was wrong on how many strings of minilights make up each min-tree. Its FOUR of each color (red, green, clear), not 2. So, the K-A-W reads were probably correct:

each tree has 12 (0.4A) strings = 4.8A per tree.... times 5!

(in my weak defense, I bought the mini-trees from a retiring member here this year and was guessing at the make-up)

 

Regarding the voltages:

I tested the voltage at the source (GFCI) and it read 120V

The extension cord in question was 15gauge, rated for 13A :-(

 

Looks like I have some major electrical work to resolve!

 

The odd thing is I definitely have spots in the sequence where ALL minitrees are lit all 3 colors.... so that would be like 40+ amps peaking (even if just for a second)- how did the circuit not trip sooner?

[Dave Batzdorf]

Balancing your current load is a fine art.  I have 12 controllers on 2 60a subpanels.  I am within .5a between the two when all is on, which is very rare or even not at all, mostly due to the 9 spots.  Normally only 3 are lit at one time.  Some of my controllers are single feed inputs, meaning only one cord on the LOR box.  I am running about 95% incan so I do have a significant draw.

 

Knowing my exact current draw I am able to taylor my LOR boxes to the dispay.  This way I only need to run 16ga cords to the LOR.  My mega tree (9k lights) is the biggest issue.

[need lights]

You are welcome dgrant.

Keep in mind that for extra long wire/cord runs you must increase the wire gauge to compensate for voltage drop. So 14 guage wire, typically used and rated for 15 Amps, may be too small for extra long runs. You may need #12 Awg or even #10 Awg depending how far you are running these cords.. Another hazard of using too small of a conductor is that it can get hot when it's rating is exceeded which could result in fire. You can search for voltage drop calculations on the internet.

[Tim Fischer]

The odd thing is I definitely have spots in the sequence where ALL minitrees are lit all 3 colors.... so that would be like 40+ amps peaking (even if just for a second)- how did the circuit not trip sooner?

Circuit breakers work on a curve that matches how the wire would heat up.  The larger the overage, the faster it will trip.  But it won't trip instantly unless you have a huge overage, or a short circuit.  (Short circuits actually trip the breaker magnetically, not via the heat curve)

[lowepg]

Well, I just tweaked my sequences again to drop even the occasional situation where 2 colors were lit simultaneously on my minitrees.... that should drop that max load from ~20A (3 colors, ALL lit) to a more comfortable 8A per controller. I tried just dropping from 3-color to 2-color but it was still popping up over 16A!

This should also make the load on my 16GA extension cords a lot safer.

I'm also going to have my electrician come back out and add another 20A breaker (or two!) to my current outdoor box. Any suggestions before i pay for this work to be done?

For instance, it will likely be alot cheaper to keep the recepticle for the new line on the side of the house, and then just run extension cord to the front lawn locations.... however, I was thinking it would be pretty awesome to have a recepticle in the front yard- closer to "the action", I suspect this would add a lot to the cost though if they have to trench a line out into the yard.... I wont bother sharing how far over budget I already am this season (I blew past budget when I had to buy 2 extra controllers!) :-)

[Tim Fischer]

For instance, it will likely be alot cheaper to keep the recepticle for the new line on the side of the house, and then just run extension cord to the front lawn locations.... however, I was thinking it would be pretty awesome to have a recepticle in the front yard- closer to "the action", I suspect this would add a lot to the cost though if they have to trench a line out into the yard.... I wont bother sharing how far over budget I already am this season (I blew past budget when I had to buy 2 extra controllers!) :-)

It's worth having them quote it.  It's much more convenient to have the outlets close to your display, and electricians are very good at getting wires across finished spaces with minimal damage.  We redid our kitchen this summer and they had to run wires to a downstairs bedroom across finished space - they were able to do it with only a single 4" hole in the bedroom ceiling, which was "repaired" with a round electrical box and blank decorative plate so it can be used again in the future if necessary.