Carport Electrical Fire While Charging

[Bill R.]

Last Friday I parked the Volt in my carport and plugged it into the same 120v outlet that I have been using for the last month. An hour later the house experienced a power surge. Seeing that a pair of (ganged) 70 amp circuit breakers that feed the sub panel in the carport had tripped, I went to the carport. There I smelled smoke and saw that a slot, 1 1/2" long and 1/4" wide, had been burned through the steel faceplate of the sub panel.

When the responding fire fighters removed that faceplate we saw that a feed wire had partially melted its insulation and had completely burned through under the slot.

My electrician replaced the burned out feed wire (black, No. 6 size) and determined that the failed wire had been
supplying not only the Volt's outlet, but two air conditioning units, resulting in an imbalance, such that the black side of the circuit was carrying almost 20 amps more current than the red side. The Volt's outlet has now been re-wired to the red side and I have used it for an uneventful charge cycle.

I certainly do not blame the Volt in any way, as it was simply the (big) straw that broke the back of the electical system. Clearly I had too much on one circuit. No one, so far, has been able to tell me why the feed wire burn through occured prior to the circuit breakers opening.

I plan to have an independent electrician review all circuit loads and I offer this only as a cautionary tale to other Volt owners and welcome feedback from this group.

[WVhybrid]

Having a dedicated circuit for charging your car is a cautious step I recommend to anyone planning on charging an electric car.

I created two new circuits in my garage for car charging. A 240 circuit, wired for 30 A, but with a 20 A breaker. The 240 v circuit has an secondary disconnect between the breaker and the Voltec charger station.

I also added a 15 A 110 circuit, for charging with the portable charge cord. The new 110 v circuit has also improved flexibility for tools and appliances, like running the vacuum cleaner.

WVhybrid

[PatsVolt]

I have a 40A 240V subpanel that only feeds the Volt. I did also put a 120V 20A off each sided of the feed to run my comprssor and/or add as a 120V charge circuit in case the 220 unit fails. Also added in a surger supressor and TED to monitor power usage by the Volt.

[voltage692]

I for one don't appreciate the shock headline of your post. Are you trying to be like Fox News?

It should read -- I melted some wires and a fuse in my fuse box by overloading my circuits because of incompetent electricians.

Anyone looking at your headline would think the whole car port was destroyed along with your Volt.

[DonC]

I for one don't appreciate the shock headline of your post. Are you trying to be like Fox News?

It should read -- I melted some wires and a fuse in my fuse box by overloading my circuits because of incompetent electricians.

I thought the title was fine and found the subject very interesting. Obviously YMMV.

[Mark Z]

Two electric circuits using a common neutral must be supplied from two breakers that are on different 120 volt mains. Having a dedicated circuit breaker with a separate hot, neutral and ground wire from the breaker panel to the outlet will avoid the problem.

This issue is critical because X-10 home automation can fail when circuits are on different sides of the two 120 volt mains. Switching the wires in the circuit breaker panel is an easy fix, but can be a disaster if common neutrals are used and two circuits use the same neutral with both breakers on the same main. If one is a hair dryer and the other a toaster, the neutral will overload when both devices are on.

Because former owners of a home may have switched wires in the circuit breaker panel, it is wise to have an electrician check for this as part of home inspection or when adding any high amperage appliance to a 120 volt circuit where the panel has not been checked.

[Number719]

70 amp circuit breakers...black, No. 6 size

I plan to have an independent electrician review all circuit loads

Using http://www.electrician2.com/calculat...cpd_ver_1.html and plugging in 50 amps of continuous load shows a 70amp breaker and #4 wire should be used. And if you raise the ambient temperature drop down box or click the box for feeding branch circuits the wire size gets even bigger. I think your plan to have another electrician review this installation is wise. You may have wire that is too small or the 70 amp breaker may be too big.

[Chevrolet Customer Svc]

Glad to hear that was the only extent of the damage and you and your Volt are all right Bill!

Volt Advisor Trevor
Chevrolet Volt Advisor Team

[N Riley]

Glad to hear that was the only extent of the damage and you and your Volt are all right Bill!

Volt Advisor Trevor
Chevrolet Volt Advisor Team

+1 on that!!!

[taminatorv]

I was charging our Volt in one of the garage outlets for the past month. Everything was fine until one hot day when the central A/C came on while the Volt was charging. About an hour into using both, a breaker tripped and both died. When I poked around, I found that the furnace/air handler shares the same 15 amp breaker as all of the power to the garage.

The house was built in 1984 and the electrician I called said that code allowed that back then. I had him wire a dedicated outlet to a 20 amp 120v circuit and all is well. Of course, the weather has been cool ever since :-) He also found that ground from PG&E had broken off, causing my lights to flicker, and it's good that I had ground from the PV system.