Travelers VS de-rating in 3 way switching

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SparkyRules

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Per de-rating. This is current carrying conductors VS Conductors actually carrying current. If I have 8 sets of travelers ( 2 per) in a conduit (16 conductors) between 8- 3 ways switches , I see 8 current carrying conductors not 16 as there is no way you could ever have more than 8 of them hot at any time. How does the code see this, (outside of common sense)??? (Assume this is 1 ph, so the 1 neutral in conduit does not count)
 
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Half of the travellers of three ways are not counted for derating. Will get you the code section in a moment.

cant find it exactly atm but somewhere in 310.15
 
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SparkyRules said:
Per de-rating. This is current carrying conductors VS Conductors actually carrying current. If I have 8 sets of travelers ( 2 per) in a conduit (16 conductors) between 8- 3 ways switches , I see 8 current carrying conductors not 16 as there is no way you could ever have more than 8 of them hot at any time. How does the code see this, (outside of common sense)??? (Assume this is 1 ph, so the 1 neutral in conduit does not count)
Click to expand...

It's not about whether or not the conductors are "hot", as in connected directly to the ungrounded voltage, but rather about the conductors that carry current.

You count neutrals, due to the fact that it is a mandatory part of the return path. Unless you have line-to-line lighting, which is rare.
You count only the number of hots, that can simultaneously carry current. When the switching state alternates to only one of the two hots being connected, you only count the one that can simultaneously be connected.

You do not count the EGC as a CCC under any circumstances.
 
SparkyRules said:
Per de-rating. This is current carrying conductors VS Conductors actually carrying current. If I have 8 sets of travelers ( 2 per) in a conduit (16 conductors) between 8- 3 ways switches , I see 8 current carrying conductors not 16 as there is no way you could ever have more than 8 of them hot at any time. How does the code see this, (outside of common sense)??? (Assume this is 1 ph, so the 1 neutral in conduit does not count)
Click to expand...

Your profile says you are under the 2011 Code Cycle. Under the 2011 Code, you have 16 current carrying conductors.

This changed under the 2014 Code, where the condition "The count shall not include conductors that are connected to electrical components but that cannot be simultaneously energized" was added.
 
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david luchini said:
Your profile says you are under the 2011 Code Cycle. Under the 2011 Code, you have 16 current carrying conductors.

This changed under the 2014 Code, where the condition "The count shall not include conductors that are connected to electrical components but that cannot be simultaneously energized" was added.
Click to expand...

You mean 17 CCC's, not 16. Pre-2014, all conductors that could ever carry current, would count. Both hots per switch, and the common neutral.

In 2014, it is just one hot per switch, and the common neutral. Which is what would be consistent with common sense.
 
code art

code art

I found it in table 310.15(B)(3)(a) as added sentence... ( and if you want to be tricky, just hook up any spares as travelers, until you need em!, not that I would ever do this, but I know someone who may!!!)
 
SparkyRules said:
I found it in table 310.15(B)(3)(a) as added sentence... ( and if you want to be tricky, just hook up any spares as travelers, until you need em!, not that I would ever do this, but I know someone who may!!!)
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I'm confused; ...hook up any spares as travelers, until you need em...

You either need these extra spare wires or you don't. If you hook them up I would say that they aren't spares cause you needed them.
 
david luchini said:
Your profile says you are under the 2011 Code Cycle. Under the 2011 Code, you have 16 current carrying conductors.

This changed under the 2014 Code, where the condition "The count shall not include conductors that are connected to electrical components but that cannot be simultaneously energized" was added.
Click to expand...

Actually the intent, the meaning did not change. The CMP never intended us to count conductors that could not be energized at the same time.

This was made very clear when George Stolz had put in a proposal for this and the response was it was unneeded change.
 
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