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Amperage question


DavidPeterson
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I'm afraid I already know the answer, but wanted to check. I've got my house outline done in regular C7 lights, and while I haven't checked the actual amperage yet, my calculations aren't looking good. I think I've got 8 strings total, and if they are 5 watt, I'm coming up with 8.33(repeating) amps. The formula I'm using is watts(5)*lights per string(25)*number of strings(8)/volts(120?)

How exact is the 8 amp per channel max? The rest of the side doesn't have a whole lot of amps, I've got a string of mini lights around 4 windows and one pillar of C5 LEDs which I think comes out to less than an amp (15 strings.)

What leeway (if any) do we have if other channels are really low powerwise?

I was so concerned about max amps per side and total that I forgot about amps per channel. I have the presoldered Planet Christmas controllers (CTB16PC) with the heavy duty heatsinks.

Also, how many amps does the controller itself take?

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The 16PC with heavy duty heat sinks is rated at 8 amps per channel, 15 amps per bank, 30 amps total.

If you are concerned about going over the amps on the channel, why don't you just reduce the intensity from 100% down to about 80% or so?

Dan has said in the past that the boards can handle a bit more than what they are rated, but I have never tried it.

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You are so close I would definitely measure with a Kill-a-Watt meter or something similar. I also outlined my roof in three colors and they all are off their mark. You may actually be just under the 8A max.

-Jeff

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lonewolvie wrote:

These strings have a 5 amp fuse in the plug given that there were no modifications.


They aren't all plugged into each other, so the string fuses wouldn't be tripped.

I measured it with a Kill-a-watt, 8.8 amps. So right now I'm working on modifying my sequences so that it maxes out at 85% power. I could probably do 90% but wanted a little more leeway.
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DavidPeterson wrote:

I'll definately get a Kill-a-watt, I may be worrying for nothing. If I set the intensity lower, is it possible to easily change just that channel to max 80%? I really don't want to have to set down everything. I have LOR2.

Yes, you can easily change just that channel in LOR 2. Actually, I run all my incandescents at 80-85%. You can't really tell any difference between that and 100%. Helps save bulbs AND electricity.
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If you upgrade your fuses from 15 to 20 amps you will also need to change out your pigtails from 16awg to 12awg to handle the extra power load if you plan on going over 15 amps on one side. Don't quote me on this, but I think I have seen before that Dan sales the 12awg pigtails for those that upgrade there controls for this purpose.

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What's the easiest way to set the max output on the channel in LOR2? I've set the fade and intensity settings to 85% and been redoing that channel element by element. If there's a quicker way, I'd love to know it. I also don't know how to set twinkle and shimmer to 85% max. I can post in the LOR2 software forum if this question isn't appropriate here.

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DavidPeterson wrote:

What's the easiest way to set the max output on the channel in LOR2? I've set the fade and intensity settings to 85% and been redoing that channel element by element. If there's a quicker way, I'd love to know it. I also don't know how to set twinkle and shimmer to 85% max. I can post in the LOR2 software forum if this question isn't appropriate here.

You can set the max output per controller using the hardware utility.

I don't know if this effects twinkle and shimmer. Currently there is no way to make adjustments to twinkle and shimmer. However, given the nature of these effects, it should reduce overall power consumption. I should be installing my arches in a day or two. I will take some measurements.
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Jeff Millard wrote:

Texan78 wrote:
If you upgrade your fuses from 15 to 20 amps you will also need to change out your pigtails from 16awg to 12awg to handle the extra power load if you plan on going over 15 amps on one side. Don't quote me on this, but I think I have seen before that Dan sales the 12awg pigtails for those that upgrade there controls for this purpose.

This statement is a misconception. The pigtails (the output leads from each channel) are #16 and are sufficient for the 8amp per channel limit. The change that is required for uprating a controller to 20 amps per bank is to have a #12 wire cable for the source to the bank. This was only mentioned because some folks constructed their controllers with #14. Also note that for NEC approval, 20 amp feeds require twist-loc connections.

Jeff


That is correct, I should have made that more clear. You only need to change out your 2 pigtails that power the controller to 12 awg if you upgrade from 15 to 20 amps. Your pigtails that power your individual channels are sufficient enough with the 16 awg for the 8 amps per channel. I don't know anything about using twist-loc connections. If that is the case it could get really expensive because twist-loc connection cords are not cheap. I know they are widely used in stage production set ups.
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This is my understanding of 15 and 20 amp service.

As provided my NEMA (National Electrical Manufactures Association):

For 15 amp service, NEMA 1 and NEMA 5 plugs are used. These are commonly referred to as Edison plugs. NEMA 1 is your typical 2 blade plug and NEMA 5 is your typical 2 blade plug with a ground pin.

For 20 amp service, you can use a NEMA TT30 - often called an RV30, since they are common with recreational vehicles. This plug has two larger blades and the ground pin that form a triangle with the hot and neutral rotated 45 degrees.

20 amp service can also be handled with twist lock plugs with most following NEMA L5.

So you can get 20 amps without a twist lock plug, but it still a different plug none the less. I guess this is why you don't see Showtime products (UL listed) in a 40 amp configuation.

You will see some extension cords advertising 20 amp with an incorrect plug. My guess is that these cords are not UL listed.

All that being said, I would use a 12 gauge cord with an edison plug on a dedicated 20 amp circuit for 20 amp service, as I am sure many are doing.

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iresq wrote:


All that being said, I would use a 12 gauge cord with an edison plug on a dedicated 20 amp circuit for 20 amp service, as I am sure many are doing.


I agree, I mean if it will work then why not. I use 12awg ext cord for 20 amps as that is what it is rated for. I am not sure why you need any special plugs for this application. If NEMA 5 plugs work for ext cords I don't see why that can't here.
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Texan78 wrote:

iresq wrote:

All that being said, I would use a 12 gauge cord with an edison plug on a dedicated 20 amp circuit for 20 amp service, as I am sure many are doing.


I agree, I mean if it will work then why not. I use 12awg ext cord for 20 amps as that is what it is rated for. I am not sure why you need any special plugs for this application. If NEMA 5 plugs work for ext cords I don't see why that can't here.


I agree but disagree,on the plug requirements. They make a cord cap that is rated for 20a/120v. This cord cap is similar to the common 15 amp cord cap except one of the vertical prongs is turned sideways. This prohibits a 20a cord from plugging in a 15 amp recpt. But a 20 amp recpt. will accept a 15 amp cord.

On some of my PC kits a feed them with a single 10gauge cord with a 30amp twist lock connector.
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Donald Puryear wrote:

This prohibits a 20a cord from plugging in a 15 amp recpt. But a 20 amp recpt. will accept a 15 amp cord.

That doesn't make much sense why that is when clearly a 20 amp cord would work on a 15 amp circuit. I can understand though not using 15 amp cord on 20 amp circuit though, that is asking for trouble if you go over the rated cord specs.
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Cord ratings can be very confusing. #12 cable with 15amp connectors is only rated for 15amps. For the cord to be a true 20amp cord it must have 20 amp connectors.

When the code defined plug and Recpt. configurations. They are considering the cord to be the supply line of a piece of equipment. ( not as extension cords) Thus if the equipment draws 18 amps it would use a 20 amp connector to force the user to plug it in the proper recpt.

Did that help, or confuse you.

Thats my 10cents worth

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Texan78 wrote:

Donald Puryear wrote:
This prohibits a 20a cord from plugging in a 15 amp recpt. But a 20 amp recpt. will accept a 15 amp cord.

That doesn't make much sense why that is when clearly a 20 amp cord would work on a 15 amp circuit. I can understand though not using 15 amp cord on 20 amp circuit though, that is asking for trouble if you go over the rated cord specs.

You can use a 15 amp cord on a 20 amp circuit. You could use a 10 amp cord. Does not really matter so long as you are not exceeding the capacity of the cord. It's the current draw, not the amount of current that is available. Otherwise, you could not run a nightlight off a 15 amp circuit.

The other way is far worse. If you have a 20 amp load, you should not be able to plug it into a 15 amp circuit. That is why the 20 amp receptacle described about will have an input that looks like a sideways T. This allow for both a 15 amp plug (both lugs vertical) and a 20 amp plug (one vertical, one horizontal.)


So yes, technically the extension cords marked 20 amp with a regular 15 amp plug could get you in a lot of trouble.
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iresq wrote:

Texan78 wrote:
Donald Puryear wrote:
This prohibits a 20a cord from plugging in a 15 amp recpt. But a 20 amp recpt. will accept a 15 amp cord.

That doesn't make much sense why that is when clearly a 20 amp cord would work on a 15 amp circuit. I can understand though not using 15 amp cord on 20 amp circuit though, that is asking for trouble if you go over the rated cord specs.

You can use a 15 amp cord on a 20 amp circuit. You could use a 10 amp cord. Does not really matter so long as you are not exceeding the capacity of the cord. It's the current draw, not the amount of current that is available. Otherwise, you could not run a nightlight off a 15 amp circuit.

The other way is far worse. If you have a 20 amp load, you should not be able to plug it into a 15 amp circuit. That is why the 20 amp receptacle described about will have an input that looks like a sideways T. This allow for both a 15 amp plug (both lugs vertical) and a 20 amp plug (one vertical, one horizontal.)


So yes, technically the extension cords marked 20 amp with a regular 15 amp plug could get you in a lot of trouble.
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Right, that makes sense and I know that you can use a 15 amp cord on a 20 amp circuit, you just cant exceed the 15 amp rated capacity of the cord.

What is a little disturbing is if you buy a cord that is rated for 20 amps and says it is 20 amps, but the the plugs on it can't handle 20 amps how do you know they can't. I didn't think the plugs mattered as much as the cord that is carrying the power as far as ext cords go. I know in special circumstances you will need a tru match plug and cord depending on the application. But if you buy a ext cord that is rate for 20 amps, you would think the entire cord and plugs is rated for 20 amps.
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Texan78 wrote:

What is a little disturbing is if you buy a cord that is rated for 20 amps and says it is 20 amps, but the the plugs on it can't handle 20 amps how do you know they can't. I didn't think the plugs mattered as much as the cord that is carrying the power as far as ext cords go. I know in special circumstances you will need a tru match plug and cord depending on the application. But if you buy a ext cord that is rate for 20 amps, you would think the entire cord and plugs is rated for 20 amps.

You are almost there. It's not that a 20 amp extension cord with regular plugs can't handle 20 amps, it can. Its the fact that this cord can be plugged into a circuit that was designed to only carry 15 amps. Using special connectors, prevents plugging a 20 amp device into a 15 amp circuit.
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iresq wrote:

Using special connectors, prevents plugging a 20 amp device into a 15 amp circuit.


Ok I see what you are saying now. I think I was just misunderstanding you. Yea I know about the special plugs for 20 amp devices so you don't plug into 15 amp circuit, that would be bad. I thought we were talking strictly about ext cords.
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