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Service entrance


Mark P
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What Chad said,

Is that insulator anchored to anything or simply caught in a tug-of-war? That grounded cable from the pole is designed to carry the weight of the triplex plus the load of those 120-volt circuits. That original grounded conductor to the box is not designed to carry that much weight. If that insulator is hanging in the air and that grounded conductor is carrying all of the weight, and that clamp fails, everything in the house is going to become 240 volts, no? Won't that fry a whole lot of stuff that's plugged in and turned on at the time?

ONE TEAM - ONE FIGHT!!!

Mike

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If that insulator is hanging in the air and that grounded conductor is carrying all of the weight, and that clamp fails, everything in the house is going to become 240 volts, no? Won't that fry a whole lot of stuff that's plugged in and turned on at the time?

I don't believe that you would end up with 240 volts on all circuits. The earth ground is in place to provide a return path to the transformer. It would be at a much higher impedance however, you would still have 120 volts. The higher impedance will cause problems with some appliance. The grounded conductor looks to be undersized and poorly connected to the service conductor.

Even if there was no earth ground / return path, I'm still not sure you would get all 240 volt circuits. I would think you would have functional 240 volt circuits and non-functional (open) 120 volt circuits.

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I just fixed my post. I didn't mean to say "Is that insulator grounded" I meant to say "Is that insulator anchored to anything." If that little splice clamp lets loose, I suspect there's going to be a lot of resistance along that earth ground path. Stuff might not get a full 240 volts but I think it might run pretty hot - at least hot enouph to damage some stuff.

Then again, what the hell do I know about electricity? I'm the guy who used to be so afraid of panels that I'd open service panels by leaning to the panel from nearly 4 ft. away and leaning on the wall so that if I got zapped my body weight would pull me off the panel and I wouldn't stand there frying.

ONE TEAM - ONE FIGHT!!!

Mike

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Originally posted by SWagar

If that insulator is hanging in the air and that grounded conductor is carrying all of the weight, and that clamp fails, everything in the house is going to become 240 volts, no? Won't that fry a whole lot of stuff that's plugged in and turned on at the time?

I don't believe that you would end up with 240 volts on all circuits. The earth ground is in place to provide a return path to the transformer. It would be at a much higher impedance however, you would still have 120 volts. The higher impedance will cause problems with some appliance. The grounded conductor looks to be undersized and poorly connected to the service conductor.

Even if there was no earth ground / return path, I'm still not sure you would get all 240 volt circuits. I would think you would have functional 240 volt circuits and non-functional (open) 120 volt circuits.

You'd have a big mess. If the grounded conductor connection at the weatherhead were to come apart, the 120-volt circuits would be subjected a mish-mash of widely varied voltages. The earth ground will have far too much resistance to maintain them at 120-volts. Only a small percentage of the current would return to the transformer that way.

The voltage on any single circuit will depend on what's plugged in and turned on in that circuit as well as in all of the circuits on the opposite pole.

For example, consider the refrigerator circuit. It gets its power from pole A but it can't return via the neutral because that's gone. So the power runs through all available paths back to the transformer in proportion to their resistance. Some of its current runs through the grounding electrode, through the earth and back to the transformer but not much because there are 15 or 20 lower-resistance paths back to the transformer through various light bulbs, the vacuum cleaner, the computer, the dishwasher, the washing machine & the plasma tv.

The actual voltage would be close to 240 volts but would be constantly changing as these various items blew up and removed themselves as viable return paths.

- Jim Katen, Oregon

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