- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I went to a call that was for the breaker to a water heater that was tripping. Little background.....
This is a mobile home and of course the service panel is outside.
In the house panel the bus was burnt where the WH breaker was so a small disconnect was mounted on the outside main panel. Now this was done by friend of HO and not at all correct. They just ran #10 from the load side of main breaker to the disconnect. The disconnect has a 30A breaker for the WH. A 10-2 UF wire was ran to the WH.
When the 30A breaker in the disconnect is turned on it trips immediately. After checking I thought the water heater had a short but found it doesn't. After further checking, I found that the feed from the main breaker to the disconnect is shorted. Then I discovered the main breaker is bad. One leg is dead. The conductors to the disconnect, when disconnected, are not shorted.
My question is why or how would only the breaker for the WH trip and not anything else in the home? How could just losing one leg of the main cause a short on a 240V load?
I'm going back to replace the outside panel/disconnect and will know for sure if that is all that is wrong. I just can't seem to grasp why it affects only the WH breaker.
This is a mobile home and of course the service panel is outside.
In the house panel the bus was burnt where the WH breaker was so a small disconnect was mounted on the outside main panel. Now this was done by friend of HO and not at all correct. They just ran #10 from the load side of main breaker to the disconnect. The disconnect has a 30A breaker for the WH. A 10-2 UF wire was ran to the WH.
When the 30A breaker in the disconnect is turned on it trips immediately. After checking I thought the water heater had a short but found it doesn't. After further checking, I found that the feed from the main breaker to the disconnect is shorted. Then I discovered the main breaker is bad. One leg is dead. The conductors to the disconnect, when disconnected, are not shorted.
My question is why or how would only the breaker for the WH trip and not anything else in the home? How could just losing one leg of the main cause a short on a 240V load?
I'm going back to replace the outside panel/disconnect and will know for sure if that is all that is wrong. I just can't seem to grasp why it affects only the WH breaker.