Electrical Gurus

[Cruez]

I got a problem....

I have a circuit breaker in my house that is heating up....eventually tripping...

I have swapped out the breaker (30 amp double) for the water heater and its not the breaker...

I want to check the resistance on the circuit but I have no clue what it should be for 12 guage copper wire.

The total round trip loop is around 35-40 ft.

Anyone know what the resistance should be???

Edit...oops... 40 ft.....not 400

[skuz]

For a simple wire, it should be very low, near 0. Maybe a few ohms, but not much.

I'd rather think the problem is at the other end of the wire.

[mlee97]

Feel the wire feeding the breaker, is it warm? is the wire copper or aluminum? Is the wire oxided? how old is the installation/ breakers? Any idea of the current draw on Items using the circuit?
I STRONGLY suggest visually inspecting every outlet/fixture on the circuit. A hot breaker is a powerful clue to several electrical fire dangers. Don't ignore it! The problem is probably a broken outlet or switch somewhere in the circuit or perhaps a nail or screw in the wall has hit the wiring. Good luck, Call an electrician, it's cheaper than a fireman.

[crouse]

I doubt it's the wire itself, although that is possible since it's only 12 guage wire. It could be the water heater.....(I assume it's electric). More than likely the water heater is somewhat old and has sediment in the bottom. This inhibits the heating element from heating the water properly and usually just causes the water heater to run alot. But sometimes it can cause a circuit breaker to trip. For a double 30 breaker you should however be running 10 guage wire at a min.

Hth's

[VHockey86]

I agree about the 10 gauge wire with a 30 amp breaker

Just pray you dont have any worn wires creating a short. How old is the electrical wiring in your house? If you actualy wanted to calculate the nominal resistance... Resistance = resistivity * length / cross-sectional area

[Brainchild]

Is 30 amp breakers the recommended amperage for the water heater? think mine is 40 amp on a 10 gauge wire.Does it vary from manufacturers?

[jerrygarcia]

Your wire size is determined by the load of the particular appliance. The breaker is determined by the wire size.

14 gauge - 15 amp
12 gauge - 20 amp
10 gauge - 30 amp
8 gauge - 40 amp
6 gauge - 50 amp

and so on and so on.

You are more than likely over burdening your wire which is very dangerous. Age of the water heater? An electric water heater is a resistive load so it would heat up your wire and the breaker is doing exactly what it is supposed to be doing. Your wire is not.

That's the reason not to run an electric space heater on an extension cord. Same theory.

[jerrygarcia]

Originally posted by brainchild
Is 30 amp breakers the recommended amperage for the water heater? think mine is 40 amp on a 10 gauge wire.Does it vary from manufacturers?

Depending on the load/size of your particular appliance. There is a rating plate on the top more than likely. 40 amp = 8 gauge.

[jerrygarcia]

Originally posted by mlee97
Call an electrician, it's cheaper than a fireman.

I am a fireman and an electrician.

Fireman at the moment(@ the station now).

[Cruez]

Its a brand new house, brand new wiring ,brand new water heater...

I checked the wires, no corrosion. I tested the wires back to the panel=no problem, I checked from the cut off to the water heater=no problem.

It is 10 guage wire on a 30 amp breaker...

None of the wires were getting hot.. just one side of the breaker...

I just unhooked everything and put it back again...

The breaker seems to be ok now... I am assuming one of the connections may have not been making good contact....

We will see.... I'll check it later when the water heater shuts itself off..


thx guys..