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Small Cabin Forum / Off-Grid Living / Needing help with an electrical question
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nicalisa
Member
# Posted: 13 Nov 2011 22:03
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Hi there everyone. I hope that you are having a great fall. So we have some wiring, solar questions to hopefully get help with.

We have wired our cabin with 14 2. While there is no electrical service, we thought to attach this to our small solar array (130 watt solar panel, 2 12v batteries and a 3000W inverter) To test the connections (and to make sure that we wired it properly) we installed a plug end onto the end of the home run wire and plugged it into an extension cord going to the generator. This run included two switches and 2 lights. The ground wires are secured to the plastic double gang box.

Hubby plugged this into the extension cord and ran the voltage tester (like a pen that lights up when there is current) The hot was hot, the neutral was hot and the ground was hot. Ummmm........

My hubby rechecked all connections they were all wired correctly.

Any ideas what the heck is going on here.....

neb
Member
# Posted: 13 Nov 2011 22:57 - Edited by: neb
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Ok are you running 120 or 240 volts. You may have 240 coming out of the gen. putting voltage on both the leads on the plugin you installed. You have a hot leg on the ground someplace. Check the plugin if 120 volt that you only have one hot wire connected to it. In that plug in you have 3 wires one is a nuetral one is a ground and the other is a hot leg. The ground and nuetral are hot I would say because you have them bussed togather in the box.

nicalisa
Member
# Posted: 13 Nov 2011 23:12 - Edited by: nicalisa
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Hi there neb,
the generator is a gas generator that runs 120AC from the plugs.

The plug end required the 14 2 to be stripped and then termintated to the appropriate prongs for neutral hot and ground. There was no bare copper touching.

We have all of the grounds connected to the back of the single and double gang boxes on the little metal bar that is on the back for the ground.

Sigh, this is driving us crazy......

Martian
Member
# Posted: 13 Nov 2011 23:45
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If all wires are the same: ie hot, then the tester shouldn't light up. You have to have a difference in voltage for current to flow; so all hot means no difference which means no light. If you aren't blowing the generator's breaker, then you don't have a short. The neutral and ground are tied togther in the breaker box; so its impossible to read voltage between the ground and nuetral. You will read hot between the black wire and the white wire or the bare copper wire, but not between the white wire and the copper wire.

Tom

Rob_O
# Posted: 14 Nov 2011 00:06
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Induced currents can cause false positives when you are using a non-contact tester. Is you system properly grounded, and bonded at one point in the circuit?

neb
Member
# Posted: 14 Nov 2011 00:43 - Edited by: neb
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What you need is a volt meter and check what you have for voltage. And like the rest said you can get a false positive read with just a tester.

larry
Member
# Posted: 14 Nov 2011 07:56
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have you tested the circuits...such as , plug a simple lamp into an outlet ?

Bzzzzzt
Member
# Posted: 14 Nov 2011 17:25 - Edited by: Bzzzzzt
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nicalisa:

I am an electrician by trade and have been doing this kind of work for 25+ years. Rob_O probably hit the nail on the head. The Non-contact testers often give you a false positive. They are extremely sensitive. The manufacturer would rather it tell you there is electricity when there is not rather than tell you there is not electricity when there is. Fewer law suits.

They make a simple plug tester that will light up like these:
http://www.google.com/products/catalog?hl=en&sugexp=ppwl&cp=11&gs_id=1u&xhr=t&q=plug+ tester&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1366&bih=618&um=1&ie=UTF-8&tbm=shop& cid=6930323965348544694&sa=X&ei=c5PBToSDNeqvsQL8gO29BA&sqi=2&ved=0CGEQ8wIwAA

They are more accurate and will tell you with simple lights if you have it wired properly.

One thing I'm more concerned with is your ground being attached to the plastic box. The bare wires should be attached to the green screw on the receptacle and/or light switch. If you've got a light fixture attached as well from the light switch the ground wire there should be attached to the bare wire in your 14/2 romex.

I would also recommend, but not completely necessary, driving a ground rod and attaching the generator ground (usually there is a lug or a screw just for this purpose on the generator.) This will grab any stray voltages and dissipate them before they can zap anybody.

Martian
Member
# Posted: 14 Nov 2011 18:53 - Edited by: Martian
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I was curious about them having the ground attached to the clip, too. I thought they might be using a different box than what I'm used to; so I didn't say anything since I don't do wiring every day. I'm glad you mentioned it, since they don't have anything grounded as it is. Good catch.

Your recommendation of the ground rod is a good one. I was working in a metal building, and the outlet we were using was powered thru a remote breaker panel....no rod. Everytime I fired up the circular saw, if I was in contact with metal, there would be a mild shock. After much reading, I learned that I was providing the easiest path to ground for the nuetral leg. A rod at the box cured it.

Tom

MtnDon
Member
# Posted: 14 Nov 2011 20:28
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I would definitely get one of those cube testers that Bzzzzzt recommended. They can be very helpful.

Does your cabin wiring incorporate a service panel, breaker panel? Those have provision for a neutral / ground bond. A single point where the ground bar and the neutral bar are connected. There should be only one 'bond' in the system. Some generators have a bond within their circuitry. If that is the case and the generator is close by then the cabin bond connection should be omitted. Problems can also arise with inexpensive inverters. I have seen some of them release their "magic smoke" that makes them work when connected to a bonded panel.

nicalisa
Member
# Posted: 14 Nov 2011 21:39
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Hi there everyone.

So here are some answers to your questions. We have the cabin wired with 14 2. We have an electrical box with fuses. It is grounded with a ground rod to the earth that we trenched in. Before we attached the wire to the fuse in the panel, we put a male plug in on that line of 14 2. We wanted to make sure that before we wired it all in, that we tested the lines to ensure that it is correct. My hubby has finished his first year electrical training and spent a year wiring condos so he felt comfortable with this set up. So we had on line that looked like this:


male plug end---14 2---into double gang switch box---wire out to light

There are two separate home runs running into that switch box as one is a ceiling fan that we gave a dedicated line to and the other is the main cabin light.

We connected the light line to the male plug end to attach to the extension cord of the generator to ensure that it was correctly wired. The ground going to the switch was grounded to the switch. The ground for the remaining wire was attached to the metal plate at the back of the box which is used for grounding (this is per canadian code).

The second dedicated line coming into that switch box for the fan had the switch connected as well (ground connected to switch) and for run up to the fan it was grounded to the box on the metal plate used for grounding.

When we plugged the male end into the generator, The hot was hot, the neutral was hot, and the ground was hot. The ground was charging the metal ground plate on the double gang box and the entire other line (not connected to anything) was hot for both ground, neutral and hot wires as well. The entire run not connected to any electrical source was energized.

Now at this time as it was not attached to a fuse (as that end we installed the male plug into to test the run off the generator) it was also not grounded to the panel and into the earth, but we thought that it would be ok because the genny has an internal ground.

We thought that something was wrong with the run, ripped it apart and inspected. All was correct.

Could this have happened because we are using the metal plate at the back of the box for the ground...could it be happening due to connection with the generator.....

We tested another line and almost electrified the whole cabin with the plugs....even if they were not connected, they were live (all three lines testing hot) These also were grounded to the plugs as well as the back of the boxes on the ground strip.

I feel like we are being hazed by the ghost of off the grid electric.

I am sure that there is a simple something that we are both missing, but at this point I am ready to give into the ongoing need for candle light, which is romantic with my sweetie:) but less so with two young boys underfoot in a 1 room cabin without a door to our little `sleeping area`
Not really mood lighting in that situation.

Plus there is a real desire to flip on a light.....not sure why, but it would be great when we get in on dark winter nights.

nicalisa
Member
# Posted: 14 Nov 2011 22:12
Reply 


PS.
you are all wonderful and my hubby told me to tell you that the grounds are only looped around the metal plate in the back of the box and then are pigtailed together and then the ground (for all three is connected to the little green screw)

nicalisa
Member
# Posted: 14 Nov 2011 22:17
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http://www.homedepot.ca/product/non-metallic-single-gang-18-in-cu/914371

example of a single gang box like the double that we have

Rob_O
# Posted: 14 Nov 2011 22:53
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Connect the ground lug on your generator to the ground rod and your problem should go away. Without a ground the neutral and ground kinda "float" relative to the "hot" and can test hot

Have you actually tested for voltage between hot, neutral and ground or are you just using the voltage probe? Larry has the best idea, plug in a light and see if it works.

Martian
Member
# Posted: 14 Nov 2011 23:09 - Edited by: Martian
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So, you are trying to test the circuits by tieing hot, nuetral, and ground into a switch leg? The switch leg only breaks the hot lead feeding the light. So, if you make the black lead hot and the white lead nuetral, and then plug it in, you are creating paths that aren't natural. You need to tie in at an outlet where all three are present.

That box is different from what I use. It looks like it does provide a good ground thru the mounting screw. I like it.

Tom

Bzzzzzt
Member
# Posted: 15 Nov 2011 20:22 - Edited by: Bzzzzzt
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I've read your second post twice and it SOUNDS correct. I would take an actual voltage tester or a plug tester and test the output from the generator itself.

If your husband installed the cord cap on the end of the 14/2 you might want to look in there and make sure the black wire is connected to the gold screw, the white wire is connected to the silver screw and the bare or green wire is connected to the green screw. This is the American way it should be connected and I'm going on the assumption that Canada is similar, but you might want to verify that with someone in the know.

It is possible, however unlikely, that there is a problem with the wire itself. If your husband is an electrical apprentice he should have a continuity tester. If not, you can get one at any hardware store inexpensively. You can completely disconnect the wire from anything and isolate one end so that none of the wires are touching anything (putting a wire nut on each of them is the easiest way.) Then check continuity between each wire from the other end of the 14/2. bare to black, bare to white and white to black. There should be no continuity at this point. Then you might tie like the black and the white together with a wire nut and make sure there *IS* continuity between them. I'm pretty sure you have something miswired, but it never hurts to check the wire itself.


Another thought just popped into my head. When the wire comes to the first box, I think you said it was a double gang with a plug and a switch that then goes out to a light, is it possible that you have miswired the switch? What SHOULD happen is like this:

14/2 with cord end that goes to generator comes to box. Black is hot, white is neutral, bare is ground.
14/2 out to light has black switch leg, white neutral and bare ground.
Black wire from generator should be spliced with 2 pig tails, one to the top side of the switch, the other to the gold screw on the receptacle.
Black wire from light should tie only to the bottom screw on the switch.
White wires should be spliced in the box with one pigtail out to the silver screw on the receptacle.
Bare wires should all be tied together with a pigtail to the box and one to the switch and one to the receptacle.


Seeing that picture of your box is interesting. I've never seen a plastic box with a place to put a ground wire. Must be something new as I haven't been doing any residential wiring in a number of years.

I hope you get this solved. If not perhaps you might open up the boxes and take pictures of your wiring job and post them. Then maybe I could see something that might be awry.

Bzzzzzt
Member
# Posted: 15 Nov 2011 21:19
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Here's a video that I found that explains the basic steps in a light switch.

http://www.5min.com/Video/Single-Pole-Light-Switch-Wiring-80715819

This just covers the switch wiring.

MtnDon
Member
# Posted: 15 Nov 2011 21:42
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Quoting: Bzzzzzt
, but it never hurts to check the wire itself.


That reminded me of something that happened to a friend. He had something strange happening with his electrical in a newly built home. I don't remember exactly what. In the end he traced the issue down to a nail that had pierced a Romex wire and caused a connection to be made between two of the three wires.

Bzzzzzt
Member
# Posted: 16 Nov 2011 07:01
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MtnDon:

I ran into a situation a few years ago where a guy called me up because half the plugs in his trailer house quit working. Turns out, the thing had masonite siding on it and it had begun to buckle over the years and he went around and put some nails in it. When they wired this particular trailer, instead of drilling holes through the studs they had notched room for the wires on the outside of the studs and the guy had accidentally pierced one of the wires. It then took a few months for it to deteriorate and quit working. THAT was a head scratcher for sure.

Rob_O
# Posted: 16 Nov 2011 20:12
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Quoting: Bzzzzzt
THAT was a head scratcher for sure.


I'm working on one of those myself. 20's house that has been remodeled several times since it was built, and somewhere under all that "new" stuff is a buried junction box with a dead short

Martian
Member
# Posted: 17 Nov 2011 09:45
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Have you solved the problem? Inquiring minds want to know.:)

Tom

nicalisa
Member
# Posted: 17 Nov 2011 23:28
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Nope, not solved yet. Have to get back to the cabin, but we won`t be back out until after christmas due to holiday parties, kids bdays, santa shopping (and since santa is buying quads for the family, he has spent many hour shopping around for the best price:)

I have printed out your replies, and have made a shopping list for the new testers that we need and it is top of the list when we are out next.

I want to thank you all for the advice. We are going to go out with our video camera when we head out next and try to fix the electrical. We will test and video tape the experience. I will load on U tube if we still have issues so that you can view the actual situation. I will post the link to this thread so you all know it has been updated:)

Bzzzzzt
Member
# Posted: 18 Nov 2011 08:35
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nicalisa: If you need anything further don't hesitate to ask. I'm new to the cabin thing but I'm always willing to help with the electrical. )

Sparky
# Posted: 6 Apr 2012 11:28
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Another possibility, one that I've experienced. If your 14/2 going into your fuse box is connected with a standard Romex box connector and there are 2 romex cables in the same connector, you may have it clamped too tightly. This can induce stray voltage into the conductors, thus giving you a false positive with a non-contact tester. Simplest test is to plug a lamp or small radio into the circuit and power up. Just be sure that your light bulb is good or that there are no batteries in the radio.

Romex box connectors should be clamped just tight enough that the cables will not pull out, no tighter.

rayyy
Member
# Posted: 7 Apr 2012 06:54
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Nicalisa,my poor old computer running on broad band can't run a youtube video so I'm still curious as to what the problem was.Did you ever get this resolved?

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