Sub panels

[nathanlutz]

A situation was brought to me today. At his church somone put in a sub panel 5-10 years ago and for awhile now they have been burning up plugs. He said an electrician came up because the breaker tripped and when they went to reset it, out came smoke. This is not the first time this happened. The contractor found that the sub panel was fed with 3-wires instead 4, and the panel was bonded to the nuetral. He also went through and made sure that everything was tight. The plugs that are burning up are random and the breakers and plugs are sized accordingly to the load. My question is could the 3-wire system or something other than that?

Thanks for your time.

 

[Dennis Alwon]

My guess it is probably looses connections around the receptacles and breakers. It also may be the appliance or whatever that is plugged into the sockets. I have had homeowners swear the socket shot out smoke when in fact it was the vacuum plug that they plugged into the socket.

I guess I am also saying that, although not legal, the 3 wire sub panel feeder has nothing to do with this situation.

 

[tryinghard]

Check ampere loads while they operate items on these circuits, receptacles don't just burn there's a load. Also create a heavy load on the whole sub panel and check voltage to see if you are getting voltage drop.

 

[cloudymacleod]

isn't in sub-panels u cant bond the netrual to the panel, or am i wrong?

 

[Dennis Alwon]

isn't in sub-panels u cant bond the netrual to the panel, or am i wrong?

That is correct, you would need 4 wires to a sub panel unless you cable or conduit is metallic and approved as an EGC. I believe the OP knows this that is why he asked if the 3 wire could be the cause of the burn ups.

I forgot to add that the neutral and ground should not be bonded together.