what article in the nec prohibits bonding the nuetral in subpanels?

[steveng]

i am looking for the nec article on subpanel wiring methods?
thanks for any help.

 

[iwire]

Welcome Steve.

250.24(A)(5) Load-Side Grounding Connections. A grounding connection shall not be made to any grounded circuit conductor on the load side of the service disconnecting means except as otherwise permitted in this article.

 

[George Stolz]

i am looking for the nec article on subpanel wiring methods?
thanks for any help.

The term "subpanel" is not used in the NEC. For Panelboards, see Article 408.

For wiring methods, see Chapter 3. Chapter 3 is all the Articles in the three-hundreds. Article 300 gives you general rules that apply to all wiring methods, 310 gives you information about conductor ampacities.

The most effective way to use the code in this instance is to determine what wiring method you would like to use, and then refer to it's specific article to see if you can use it.

For example, if I wanted to run a 60A "subpanel" in a dwelling unit in NM cable, then I would refer to Article 334 to determine if I could, and what rules surround it's installation. The same setup in a large commercial building would likely be illegal in NM.

 

[George Stolz]

Heh heh - after looking at the title of the thread, I understand why Bob had focused solely on bonding!

Well, anyway...

 

[iwire]

Heh heh - after looking at the title of the thread, I understand why Bob had focused solely on bonding!

I was wondering what I missed.

But I do agree with all your other points anyway.

 

[steveng]

thanks for the help!

thanks for the help!

one thing i like about this forum is you can get answers to difficult questions.

i had one more question:

sirs, i was changing out a light switch in my house
and i measured the voltage from hot side to the bare copper ground wire, and only got 86volts, when i measured the other side of the switch leg, i got 27 volts,
anyone have an explanation.

 

[George Stolz]

sirs, i was changing out a light switch in my house
and i measured the voltage from hot side to the bare copper ground wire, and only got 86volts, when i measured the other side of the switch leg, i got 27 volts,
anyone have an explanation.

Yes, the circuit breaker was still on. By shutting off the circuit breaker, you don't risk a shock when replacing the switch.

Kidding aside, the 27V I can explain, but the 86V is a mystery to me.

What kind of switch was there: Threeway, single pole, dimmer?

 

[Dennis Alwon]

Kidding aside, the 27V I can explain, but the 86V is a mystery to me.

The 86 volts is a mystery especially since my tester will often read 86 volts on a 120 volt circuit. I know it is my tester but the fact that you are reading 86 makes me think you may have the same problem with the tester as I do. Often I just need to retest and I get 120 + or -.
If there is a dimmer on the circuit you may get some reading through that hence the 27 v. Is that what you were thinking George or is there something else.

 

[George Stolz]

If there is a dimmer on the circuit you may get some reading through that hence the 27 v. Is that what you were thinking George or is there something else.

I was thinking the 27v could have been induced voltage on a de-energized traveller.

 

[wireman3736]

Sounds like a bad ground, and a little induced voltage to go along with it.

 

[sparkzilla]

one thing i like about this forum is you can get answers to difficult questions.

i had one more question:

sirs, i was changing out a light switch in my house
and i measured the voltage from hot side to the bare copper ground wire, and only got 86volts, when i measured the other side of the switch leg, i got 27 volts,
anyone have an explanation.

I would look for a broken neutral. I had the same readings on a 3 way that had a broken neutral in one of the switch boxexs

 

[jeff43222]

What kind of tester are you using? I've read as much as 120V of induced voltage with my Fluke. Make sure you are using a high-impedance tester. That 86V could be induced, or, like the others have said, it could be due to a loose neutral somewhere.

 

[don_resqcapt19]

Jeff,

Make sure you are using a high-impedance tester.

If you are trying to eliminate the effects of induced or ghost voltage, you need a low impedance tester...something that has enough load to draw this voltage down so the tester does not read it.
Don

 

[George Stolz]

I think Jeff tends to say "high" when he means "low".

 

[steveng]

What kind of tester are you using? I've read as much as 120V of induced voltage with my Fluke. Make sure you are using a high-impedance tester. That 86V could be induced, or, like the others have said, it could be due to a loose neutral somewhere.

fluke TI600 , thanks for the help

 

[tom baker]

Fluke has a new stray voltage adapter, it plugs into your DMM and it must load the circuit. Also there new 117 has a Lo-Z function and built in Volt Alert.