Wiring question (2)

Jul 03, 2010 23 Replies

# 1. Putting in an outdoor (water proof and GFIC) plug for a friend. Plan is to go from the post mounted electrical panel to the house, under the house to the other side, and mount on the side of the house. I'm going to use 30 feet of 10 ga NM simply because I have it. Question: In going from the post mounted panel to the under-floor of the house (2 feet distance) can I stick the NM into a short conduit as-is, or, do I strip the sheathing while in the conduit? If no, then I will use single wires in the conduit and terminate them (and the conduit) within a box in the crawl space.



#2. I know that within electrical panels the neutral wire may only be bonded to the ground at the entrance (first) panel. What I don't know is why? What's the logic? How will a shorted appliance know or care that the neutral is grounded at several different places. Please educate me. I did try Google on this one.



Thank you, Ivan Vegvary



Having multiple grounds can result in significant voltage induced into the different parts of the circuit if lightning strikes nearby, and other "ground loop" problems. By having just one ground point, you keep the differences outside the house.

If you are not a licensed electrician you should not be doing electrical work for "friends"... You can only perform such work on your OWN HOME that you actually own without a professional trade license...

~~ Evan

If you are not a licensed electrician you should not be doing electrical work for "friends"... You can only perform such work on your OWN HOME that you actually own without a professional trade license...

~~ Evan

In the back woods environs of NYC, it is illegal to do electrical work on your own home without an electrical license. Ultimately, you will sell that house, and who knows what hidden dangerous wiring you may have installed.

"RBM" wrote

You guys should stand outside Home Depot and remind all of their customers of this.

NM cable may only be used in dry locations, not damp or wet locations. Putting it in conduit doesn't make any difference, as conduit in a damp or wet location is itself considered a damp or wet location.

So the upshot is that you can't use NM until you are inside the house (the crawl space, as long as it is dry). Outside you could use a short piece of UF cable or use conduit and individual conductors such as THWN.

The neutral conductor is normally a current carrying conductor. The grounding conductor (EGC) is not supposed to be a normally current carrying conductor. The EGC does need to be connected to the neutral at one location in order to do it job of completing the circuit in case of a fault.

However, if you connect the neutral and EGC in two different places, then you have paralleled the neutral and EGC. As a result, the EGC will be carrying part of the neutral current all the time. This can result in current where it shouldn't be (such as the metallic frame of equipment) and is a potential shock hazard.

Cheers, Wayne

LOL... There are TWO kinds of electrical work,

NEW INSTALL, which is introducing some new devices and the associated wiring for them which did not exist until you created it, for which you generally need a license, especially when you are doing this work for other people on property you DO NOT OWN...

MAINTENANCE, which is replacing some component due to damage, failure, interior decor changes or whatever... You are not generally required to have a license to do such work, as long as you are swapping out the components with ones having an identical rating and you are NOT adding new wiring...

There is a difference between the two types of work, as more skills and knowledge are required to install new work than are required to replace an existing duplex outlet that was mechanically broken and exposed the live internal components...

Too many of the "DIY" questions on this NG refer to NEW INSTALL type situations rather than simple maintenance/repair type work...

~~ Evan

I don't need a license to do work on my own home where I live, nor do I feel that it's really all that difficult to add additional receps, wire for ceiling fans, or add smoke detectors in a safe professional manner...

nate

LOL... There are TWO kinds of electrical work,

NEW INSTALL, which is introducing some new devices and the associated wiring for them which did not exist until you created it, for which you generally need a license, especially when you are doing this work for other people on property you DO NOT OWN...

MAINTENANCE, which is replacing some component due to damage, failure, interior decor changes or whatever... You are not generally required to have a license to do such work, as long as you are swapping out the components with ones having an identical rating and you are NOT adding new wiring...

There is a difference between the two types of work, as more skills and knowledge are required to install new work than are required to replace an existing duplex outlet that was mechanically broken and exposed the live internal components...

Too many of the "DIY" questions on this NG refer to NEW INSTALL type situations rather than simple maintenance/repair type work...

~~ Evan

The OP is doing a new installation at his friends house. YOU told him, "You can only

I'm just telling you that it is not legal in my area, to do new installations in your own home, as you said, and I expect, it's not in a lot of other areas as well. This has nothing to do with changing a bad receptacle.

Hi Wayne, Thank you so much for your answer to the grounding question. It was clear and concise. Now I know why!!!

Thanks again, Ivan Vegvary

Or sub-panels, 240V service for appliances, tools, or AC units. Of course union thugs often see things differently.

And in other areas you do not need to have a license to do electrical work.

Don't know what the rules are now, but years back in parts of PA you didn't need a license and there was no required inspection.

Both halves of what Evan wrote are wrong.

It is the latest episode of what-is-(allegedly)required-where-I-am-is-required-everywhere from Evan.

-- bud--

Bud, you need to teach me to articulate like you. Between Evan and Twayne, I just feel like I'm beating my head against a wall. Or maybe I just have an inability to recognize a troll when I see one.

You want your return to drop all the voltage back to the service panel, not at different points along the circuit. A GFCI breaker would see that as a problem and trip.

When the bank inspects your home before you sell it the will make you fix everything or hire an electrician out of your profit to fix it.

What would I have to fix? Please be specific, or I'll have to just assume that you're being an asshole for no apparent reason.

nate

You were doing great (as usual). You had direct experience that was contrary to what Evan said - it is stupid to challenge what you wrote.

And Evan has written the same kind of what-is-(allegedly)required-where-I-am-is-required-everywhere before.

I suspect Twayne (and westom) have fading mental ability. Evan, perhaps, sees things in black-and-white when the world is full of grays.

.

In my area, I do *not* need a license, but technically I *do* need a permit/inspection.

Given those constraints, isn't it better that people *do* ask questions when they are unsure rather than just doing it possibly wrong and failing their inspection?

nate

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