Proper wiring of general use receptacles

[don_resqcapt19]

Dreamed up, hmmm; OK. Undersized wires cause fires.


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14 AWG copper would have to be operated at 34 amps to reach a temperature of 300°C, and that is below the auto ignition temperature of almost all building materials. The voltage drop does not increase the temperature of the wire. That is based only on current.

 

[don_resqcapt19]

I would think it would be upon actual voltage, but I am not certain—though I will find out at some point.

I have my own issue with the POCO and the increased voltages. It is causing nuisance trips when it spikes up to 127V. I have a customer with this issue. They have a generator as well, which is regulated at 120V, and when it transfers; there is not an issue—It IS POCO related; I just have to prove it.


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Is that on an AFCI? Some AFCIs have internal over voltage protection to protect the electronics, but I thought that setting was closer to 150 volts.

 

[don_resqcapt19]

Sir, I did not state that the power company regulates that voltage. All circuit breakers are rated at a particular voltage and tolerance. I know for certain, that Square D is rated at 120v. This is the tolerance of the breaker, and that is the voltage we must work within. I am not certain, but believe the other manufacturers fall within the same spec.


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Yet 7.1.2.14 of UL 489 permits the circuit breaker calibration tests to be made at any voltage and either AC or DC. The tripping is only a function of the heat produced by the current across the sensing element of the breaker and the voltage plays no part in that.

 

[jap]

Dreamed up, hmmm; OK. Undersized wires cause fires.


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To the contrary, oversized wires cause fires also.

Especially if you go to put a larger size wire under a lug or terminal smaller than what it is rated for, or, make additional unnecessary splices to reduce the size of the conductor prior to terminating it.

Jap>

 

[bsmale]

Would you mind sharing the email from Square D in this forum?

Yes, it’s in pieces, so let me organize it before I post. Getting the information out of the engineer was difficult.


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[hbiss]

Getting the information out of the engineer was difficult.

Try getting them to explain why AFCIs are useless.

-Hal

 

[Seven-Delta-FortyOne]

Still, as was asked before, how do you figure VD at the end of a branch circuit, is going to affect voltage at the breaker, the beginning of the branch circuit?

 

[Strathead]

How is it worded? Does it actually say that on a receptacle circuit you must go to the last receptacle on the circuit and calculate a full load at that device?

I actually thought is broke them down to 2% 3% but you made me look. Here is the code:

C405.5.3 Voltage drop.​

The conductors for feeders and branch circuits combined shall be sized for a maximum of 5 percent voltage drop total.

 

[LarryFine]

I actually thought is broke them down to 2% 3% but you made me look. Here is the code:

C405.5.3 Voltage drop.​

The conductors for feeders and branch circuits combined shall be sized for a maximum of 5 percent voltage drop total.

So, the sizing must be based on it, but you need not actually achieve it?

In that case, the POCO is effectively off the hook, no compliance needed.

 

[infinity]

I actually thought is broke them down to 2% 3% but you made me look. Here is the code:

C405.5.3 Voltage drop.​

The conductors for feeders and branch circuits combined shall be sized for a maximum of 5 percent voltage drop total.

That seems pretty meaningless for multi-receptacle circuits. For something like a fire pump we can easily calculate the VD and compensate accordingly but how do you do that for a branch circuit with receptacles?

 

[retirede]

That seems pretty meaningless for multi-receptacle circuits. For something like a fire pump we can easily calculate the VD and compensate accordingly but how do you do that for a branch circuit with receptacles?

Agreed. Without specifying what load to use, it’s meaningless and thus unenforceable.