Everything that makes sense doesn't

[mgbinspect]

Well, for the second time in my career, I ran across the zaniest thing you can ever experience on the electrical side of inspecting.

Foreclosure: Power company comes by and puts in a meter. I show up and start throwing breakers. Everything is dandy until I throw my first 220 breaker, at which point all hell breaks loose.

Last time this happened it went like this:

New home. I inspect it. Everything's fine. The folks move in and call to tell me, "half the lights in the house don't work until we turn on the stove. Then, they do.

(The meter isn't pushed in all the way. The house only has 120 instead of 240 coming in. One bus is dead until you throw a 220 breaker. Then, the weirdness begins.) [:-graduat

[gregzoll]

That would be, because when the Breaker is closed, it is feeding the other leg. There is nothing weird about it. You figured it out, when you stated that the meter was not fully seated, which means that the POCO is a bunch of lazy bastards that do not care about their job.

[Marc]

That would be, because when the Breaker is closed, it is feeding the other leg. There is nothing weird about it. You figured it out, when you stated that the meter was not fully seated, which means that the POCO is a bunch of lazy bastards that do not care about their job.

Not quite. It's when one of the elements on the stove or oven is turned on to cook something that the lights come on. The stove itself can't work properly because there isn't sufficient voltage and the lights that now 'work' are likely dim because some of the voltage of the 120V source is lost across the stove element. The lights get whatever is left over after the stove has taken some. Some florescent ballasts may burn up if the stove element is left on too long.

The electric water heater or electric central furnace would do the same thing. The lights receive power from, and via, any 240V appliance that goes into action.

Marc

[gregzoll]

Marc, you over-engineered the original question. If the meter is only pushed in to allow one leg, a circuit that is tied through a Tandem, or tied through dual single breakers will cause this effect of backfeed. You send a voltage through one leg, and feed through the other, you get thus effect, when you complete the circuit through what ever appliance, or load that is tied into that circuit.

Basically comes down to instead of 120vac, you get 60vac through the circuit, because of load & resistance.

[Marc]

Marc, you over-engineered the original question. If the meter is only pushed in to allow one leg, a circuit that is tied through a Tandem, or tied through dual single breakers will cause this effect of backfeed. You send a voltage through one leg, and feed through the other, you get thus effect, when you complete the circuit through what ever appliance, or load that is tied into that circuit.

Basically comes down to instead of 120vac, you get 60vac through the circuit, because of load & resistance.

Hello Greg, The 2 pole breaker and the stove element (turned on for heat) are both needed to obtain this effect. So, we're both correct on that.

You get 60 Volts on the lamps only if the wattage of the stove element is the same as the sum of the incandescent lamps that are powered via the stove element (and 2 pole breaker). A mismatch in wattage yields a similar mismatch in the division of voltage between the two. If there's non-linear loads connected such as fluorescent lamps or computer power supplies then the answer becomes more complicated.

Marc