Sparks while changing outlet with circuit breaker off

DonL, I'm assuming when you say "Your copper water pipes should not be carrying current" you mean something more than just that grounding to copper pipes is unwise. Is there something about what I described that makes you think the pipes would be carrying current?

DavidV_NC said:

DonL, I'm assuming when you say "Your copper water pipes should not be carrying current" you mean something more than just that grounding to copper pipes is unwise. Is there something about what I described that makes you think the pipes would be carrying current?

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Only if you have spark flying from something connected to them.

A faulty Appliance can cause that in older homes. Water heaters and the like.

But the sparks aren't coming from the ground wire? They were from the neutral wires, both with and without the ground wire connected to the outlet.

DavidV_NC said:

But the sparks aren't coming from the ground wire? They were from the neutral wires, both with and without the ground wire connected to the outlet.

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You should find out where the power is coming from.

Measure the voltage across the two connections that have spark, Then kill your breakers one at a time, to find out where power is coming from.

Start with the 220V breakers.

You could have a bad appliance , because power has to be coming from some place.

Are you wiring a outlet that feeds a 3 way switch ?


You need a map of your new house.

DonL said:

Measure the voltage across the two connections that have spark,

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So, just to make sure I'm following what you're saying: Take the multimeter and touch one lead to each of the two neutral wires that were sparking? Would I need to disconnect the other wires from the outlet again, or can I do it with the other wires still connected? I'm trying to avoid messing with the aluminum wires as much as possible to avoid weakening them.

Are you wiring a outlet that feeds a 3 way switch ?

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Nope.

You need a map of your new house.

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Workin' on it.

You do not need to disconnect any thing.

Do you have sparks when things are connected ?


One note, If you tried measuring Voltage with your meter set to current, then the meter may need a new fuse.

You should make sure your meter is working, or kill all power.


It is best to kill all power if you do not know what you are working with.

I have confused this thread enough.

Next.


Have a Happy New Year all.

A multiwire circuit by code MUST have both hot legs turned off by the same CB. If one were installed using 'regular' single pole CBs, that's an issue (as I understand the code, which could be wrong). So, having current flowing in a box when the CB is off means there IS a problem in the wiring, multiwire circuit or not.

In order for current to flow, there must be a complete circuit and a voltage potential. At your main panel, both the neutral AND the ground should be bonded together, so you should not get a spark when connecting them together at a remote point - that requires the two leads to be at a different potential, and the resistance of the wire should prevent that from being big enough to create a noticeable spark. This is MUCH harder to prevent with AL wire, though, as it's easy to get a poor connection if you do not follow all of the rules when making up connections. The ground wire is NEVER supposed to be used as a current carrying connection...it is there as a safety lead to provide a path to help ensure the CB or fuse will protect the circuit from an overload. Grounding things also can help with near lightning misses (a direct one would damage things, a near one, properly installed, might be survived without damage).

DavidV_NC said:

...that grounding to copper pipes is unwise.

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To the contrary, it is not only wise, it is also required by code for the pipe to be bonded to the electrical ground.

The pipes needs to be grounded , but the pipe should not be used as a ground. There is a difference.

The ground is a safety, That can kill you if not terminated properly.

You should not use a indoor water pipe to obtain a ground


Ground rods and panel bonding are made for that, not water pipes in a house.

houptee said:

Or if you decide to leave it in place you can pigtail each outlet with 6" pieces of copper wire and splice to your aluminum wires with special purple wire nuts made for that purpose.
This lets you tuck the aluminum wires neatly back into the box with good tight connections and the device (receptacle or switch etc) can be pushed in and out flexing only the copper pigtails with much less chance of repeatedly flexing the existing aluminum wires.

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I have to question this repeated flexing. One does not normally re-enter a box repeatedly, so the flexing should only happen once or twice.

My suggestion for those that have aluminum wiring is to limit the current draw on their outlets. I know of landlords that simply abandoned all their electric baseboard heaters and switched to natural gas. They also wrote into the rental/lease agreement that the tenant is not to use electric space heaters.

DonL said:

The pipes needs to be grounded , but the pipe should not be used as a ground. There is a difference.

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Perhaps a reading comprehension issue whereby you missed where I said "bonded"?

The OP may have said grounded... but since he has used the wrong term with "current", he may have mistaken a ground for a bond.

LLigetfa said:

Perhaps a reading comprehension issue whereby you missed where I said "bonded"?

The OP may have said grounded... but since he has used the wrong term with "current", he may have mistaken a ground for a bond.

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LOL.


In the day Neutral was the ground conductor in a wall outlet that had a third ground connection. Do you think they ran a new ground wire ?

The bond was in the box, and inside many appliances.


I think Jim summed it up very well.


I also say again you should not play with electricity unless you know what you are working with.

jadnashua said:

A multiwire circuit by code MUST have both hot legs turned off by the same CB. If one were installed using 'regular' single pole CBs, that's an issue (as I understand the code, which could be wrong). So, having current flowing in a box when the CB is off means there IS a problem in the wiring, multiwire circuit or not.

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That does not apply to the OP's circuits, but only for newer construction subject to newer codes.

Further, as I understand it for newer codes, a breaker tripping on one leg does not require that the other leg trip also. So to say that they must be on the same circuit breaker could be misleading.

Regarding "neutral", the neutral is connected to a ground at the breaker box as is the protective ground. That's why I like to refer to "protective ground" to be clearer. That term is not going to be ambiguous to anybody.

Measuring the voltage between an independent ground an the neutral wire at an outlet can be informative. It would measure zero volts if no current is flowing, but it could be a few volts if there is significant current flowing.

Read this about making pigtails at boxes from EC&M magazine it references the appropriate NEC code article numbers.
http://ecmweb.com/code-basics/wiring-methods-part-2-3

Splices and pigtails


At least 6 in. of free conductor is required at each box. Where the box opening is less than 8 in., conductors must extend at least 3 in. outside the box opening.

In a multiwire branch circuit, don't wire a device such that its removal breaks the continuity of the neutral conductor. The only way to meet this requirement is to splice the supply side and load side neutrals together and then pigtail to the neutral terminal of the device [300.14(B)].

The opening of the neutral of a 2-wire circuit during the replacement of a device doesn't cause a safety hazard, so you don't have to pigtail these conductors [110.14(B)].

David you can download the NEC 2011 electrical code book and all other NC building codes free from this website.

https://law.resource.org/pub/us/code/safety.html

houptee said:

David you can download the NEC 2011 electrical code book and all other NC building codes free from this website.

https://law.resource.org/pub/us/code/safety.html

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Very nice. Thanks for sharing.

Location does mater.

We can have a outhouse here, If we do not modify it.

To put in a Toto you need a permit. And you need a ground fault interrupt on the toilet seat heater.


Have fun everyone.

DavidV_NC said:

I just purchased a 1970 house with aluminum wiring. I'm going to replace the old outlets with aluminum-rated ones. I just went to replace the first one and when I had the circuit breaker off and was disconnecting wires, the neutral wires started sending off sparks when they shifted. They continued to do this after the hot wires and ground were disconnected. My multimeter indicated there was no current going through the outlet.

I assume the sparks indicate a problem, but I'm very much a novice when it comes to electrical work. Any help in figuring out what might be wrong would be appreciated. I did finish up installing the new outlet, as I figured that was safer than having loose wires.

Bonus question: When getting the wire under the screws on the new outlet, I couldn't help scratching it a bit with my pliers. I've heard that scratches are particularly bad in aluminum wiring because it becomes a weak point during later heating and cooling expansion and contraction. How much of a problem is light scoring along the surface of the wire?

Thank you.

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What you have is a multiwire circuit and when one side is off there is still current on the other side returning through the neutral. The grounding and bonding of the system plays no role in the problem at all