Burned Circuit box.

[usnthedog]

A/C quit and called mobile service. This is what he found. A/C neutral burned in two. Reconnected and all has worked fine. 6 week trip. Limited loads and checked a lot. Ready to fix. No heat damage to hot wires. Would a loose neutral to A/C cause this? Your thoughts apprciated. I hope the picture shows.

Jeff

 

[Lynn1130]

It is hard to tell what happened there but the photo looks like acid damage from a battery and then an overheat followed. Could acid have worked its way up or down a connection to the block?

 

[danemayer]

The neutral wire handles the return current from both hot legs and if it's loose, the high resistance will cause enough heat to do what your picture shows. It looks similar to the inside of my transfer switch 18 months ago.

I'd guess you were having some unexplained symptoms along the way. Like hair dryer tripping the GFCI outlet in the bathroom. Perhaps other intermittent electrical problems.

A partial failure on neutral can also create high voltage scenarios where instead of 120V AC, some outlets or appliances are getting much higher voltage. Hopefully you didn't experience any appliance failures.

 

[Gaffer]

Classic case of a loose connection.

 

[Bob&Patty]

My suggestion would be...replace the whole buss bar. You will probably never get the screws loose anyway. You had a loose neutral wire somewhere.

 

[usnthedog]

Thanks. The box is in front of the door near the floor. No acid but maybe water. No indicators just no A/C. The fact that so many were burned bothers me. I have a new box coming. When I cut the neutrals loose none were loose. I'm very thankful that it didn't flame.

Jeff

 

[danemayer]

If you have generator prep, you should open the automatic transfer switch (power disconnected) and check the condition of wires there.