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#19191 - 12/21/02 06:16 PM Service Change Gone Wrong????
Electric Eagle Offline

Registered: 04/20/02
Posts: 928
Loc: Alpharetta, GA
Have you ever had things go bad in a house after a service change?

We upgraded a 200 amp service to 400, keeping one existing 200 amp panel and adding another. Everything seemed to go fine, but this morning one of my guys went to do some more work at the house and the customer said they had a burning smell in the bathroom and their cable modem was bad now. First they should've called as soon as they smelled the burning, but thats beside the point.
As it turned out, the GFI in the bath melted down, the cable modem or its power supply was fried and a surge strip melted down. That's all we know of at this time. I'll try to post pics of these devices later. What could've caused this? I'm thinking the POCO didn't turn the house disconnect off or the pole and the either hit line to ground or line to line. Unfortunatey none of our guys was there when the POCO did the switch over to the new mast.

One side note. The house was being served by #2 AL triplex overhead, from the house's original 100 or 125 amp service. We now have a 400 amp service and guess what? It's still being serviced by the original #2 AL. I'm going to talk to the engineer for the POCO about this, because he told me they would upgrade their cable, but they didn't.

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#19192 - 12/21/02 06:34 PM Re: Service Change Gone Wrong????
Edward Offline

Registered: 12/14/02
Posts: 309
Loc: California
Why do you think that a hot to ground when connecting the service will cause that melting problem?
I aasume that the utility connects the grounded conductore first then the ungrounded conductors. S if the grounded conductor is connected first tehn your massed is grounded through the box and any touching from the hot to the mast will open utility OCPD.

Your drop should be at least 3/0. Here in california i just had the same project i had to go underground feed. with 3/0 conductors in 3" PVC. SCH80.

Good Luck.

You know something just poped up in my head.
The utilities probably did not turn the main off. And they connected the hot conductors first so two hot conductors without a neutral creates 240Volts across the load. (just like a multiwire branch circuit wiring where the neutral is lost and the voltage240 drops across the load according to the resistavity of the load)
So in this case there was only the modem and the GFCI on the load so both devices saw 240v across them.

Just a thought.


#19193 - 12/22/02 05:51 AM Re: Service Change Gone Wrong????
sparky Offline

Registered: 10/18/00
Posts: 5545
mmmmmaybee.....was the service main left on during the swap over??

#19194 - 12/22/02 06:44 AM Re: Service Change Gone Wrong????
electure Offline


Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
What different worlds we live in!
Southern CA Edison generally won't replace a drop on an existing installation just because the service capacity is increased. Their reasoning is that the load hasn't changed, and they'll leave that #6 triplex forever.
Also, because of liability concerns, they will never turn a breaker on or off.

#19195 - 12/22/02 02:48 PM Re: Service Change Gone Wrong????
Chris Rudolph Offline

Registered: 05/01/01
Posts: 160
Loc: Winter Park,Fl USA
I agree with the guys in the above post.It sounds like the noodle was lost and those appliances that are sensitive to 240 volts got zapped.This happened to me and I lost my desktop power supply ,blew a capacitor in a TV power section toasted a VCR and a garage door opener transformer.I hate it when that happens.

#19196 - 12/22/02 05:30 PM Re: Service Change Gone Wrong????
Electric Eagle Offline

Registered: 04/20/02
Posts: 928
Loc: Alpharetta, GA
I went back this afternoon to see what it would take to fix the cable modem. It was just the 12v power supply. So all together I've spent $32 to remedy the customers problem. Out of good will I'll absorb these costs, but I'm still going to let the POCO know what happened and see what they say caused it. If $32 is all it cost me, then I guess it could be worse.

#19197 - 12/22/02 10:30 PM Re: Service Change Gone Wrong????
Trumpy Offline


Registered: 07/05/02
Posts: 8552
Loc: SI,New Zealand
Could you discount a Lightning Strike on the
lines, upstream of the Installation?.
This is in an Overhead reticulated area?.
We have problems like this over here in NZ, all the time, our Earthing(Grounding), needs to be larger because of this risk.
We also install Surge Diverters on the incoming Mains.
Your advice please?-
Let's face it, these days if you're not young, you're old - Red Green grin

#19198 - 12/23/02 05:39 AM Re: Service Change Gone Wrong????
mountainman Offline

Registered: 01/29/02
Posts: 54
Loc: Richmond Va. U.S.A.
I had the same thing happen and it turned out to be the grounded conductor was not terminated in the meter base. This will cause GFCI's to burn.

#19199 - 12/24/02 07:51 AM Re: Service Change Gone Wrong????
CRW Offline

Registered: 02/11/01
Posts: 160
Loc: Bethlehem, PA USA
who didn't terminate the grounded conductor?


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