Question for the electrical experts

[Hagar]

I have a room that has been heated with 240v electric baseboard. It stopped working. Without testing I replaced the thermostat. No change. Replace the heater, no change. I did get zapped changing the heater. No comes the part I don't understand. I used a voltmeter (cheap one), I can measure 120v between either leg and ground but between the two legs nothing. The heat was working very recently, another baseboard in another room connected to the same circuits works great. Any thoughts?

Thanks

 

[BB_TX]

Sounds like you lost one leg of the 220. Maybe bad breaker, bad connection, etc. If one leg is open from the breaker, it would still read 120 VAC on each leg because it would be reading it thru the heating element. Check the 220 as it comes out of the breaker. If it is there, then check all your connections thru out the circuit.
Oops. You said it was on the same circuit as one that works. So carefully check all connections in the one that doesn't work. If the two heaters come from the same circuit, then there must be some connections somewhere tying the two together. See if you have 220 at that connection point.

 

[hhw]

Hello;

1. You need a complete circuit to get a full reading. Sounds like you have the old type of 220 wire set up, black hot, white hot, ground? If so, to get the full 220 read on the meter, you need com to ground and "hot" to both white and black?

2.If you are reading 120 on each leg, you have from the entire breaker.

3. If you have juice tol the hook up to the unit then all is fine with the line.

4. If the thermostat is working properly, and calling for heat (juice) when turned up fully, then the unit should work.

5. If there is a "break" in the line between the thermostat and the unit, it will not call for heat.

I think I said that all in the order it should be? Hope it helps

 

[hhw]

Just in case I read your post wrong, I'll add this;

If you hook your meter up at the end of the run on let's say 10-3 with ground, and you hook COM to white and you then hook up the "read lead' of the meter to red you shold read 120VAC. If you then hook the "read lead" to black you should also read 120VAC.

If the above is the case, then you are getting the correct voltage to the end of the run. It sounds like somewhere between the thermostat and the unit is the problem. I am assuming that the thermostat is "wall mounted" remote of the unit?

 

[BobReeves]

</font><font color="blue" class="small">( Just in case I read your post wrong, I'll add this;

If you hook your meter up at the end of the run on let's say 10-3 with ground, and you hook COM to white and you then hook up the "read lead' of the meter to red you shold read 120VAC. If you then hook the "read lead" to black you should also read 120VAC.

If the above is the case, then you are getting the correct voltage to the end of the run. It sounds like somewhere between the thermostat and the unit is the problem. I am assuming that the thermostat is "wall mounted" remote of the unit? )</font>

Like someone else has said, this is true only if the heater isn't hooked up. If the heater is hooked up, the two hot legs are tied together through the heating coils and you will read 110-120 volts even if one leg is not connected to the breaker.

 

[BB_TX]

Let's see if this attachment will work. A circuit that sounds like yours. Shows one good ckt, one bad ckt. Dashed lines represent meter leads and readings.

 

[Hagar]

Thanks for all the replies. So it sounds like a "break" at the junction splitting to the two rooms. Great, its in the attic with a little access hole. Can't imagine how that happened. They were wire nutted and taped (at least I think I taped'em). It was about 20 years ago.

 

[AntrimMan]

The only way this can happen,
leg to grd = 110v
other leg to grd=110v
leg to leg = 0v
is if the hot legs are taken off the same side of the buss.
This way there is no phase difference to induce the voltage.
You effectively have a 110v circuit, not 220v.

That said, let me be fully truthful in that I am not an electrician.
I can however definitely tell you it is not caused by a gas, diesel or water leak.

All the best,
Martin

 

[kensfarm]

"I did get zapped changing the heater."

W/ the breaker off?

 

[mark1]

Question?? You got zapped with the breaker off?? This is a 220 breaker Or actually 2- breakers tied together so 2 110V circuits are switched on and off?? or did you wire the circuit seperatly using 2 breakers that are not tied together?? /forums/images/graemlins/confused.gif