aftershock
Senior Member
- Location
- Memphis, TN
Scenario:
Storage company. One of these places where people go rent, store things, ect. Rows of buildings with pull down doors.
OK. These building have wall pack lights on them. Metal Halide (sp)
1 20 amp circuit fed with #10 (for voltage drop) thhn, underground in pvc.
1 circuit feeds 3 buildings with a total of 8 100 watt fixtures per.
The conduit is run underground. It comes up into the building to a JB located on one of the corner storage areas facing inside. conduit then leaves this JB , goes back underground to feed the next building. then the third. From the JB inside each building it feed through a conduit run to a central JB which then braches off to any light located on the building. There is also one convienant outlet on the middle building.
Last week I got a call that the breaker was tripping. I checked with an amp clamp and the circuit was pulling 40+ amps. This is causing the trip.
Customer tells me the a worker plugged a circular saw into the outlet on the building and when he used it, this cause the breaker to trip and it has been doing this since. I replaced the GFI just to be sure. It was on a dead end just FYI.
I did not have time to finish that day so I re scheduled for today. I go back out with the intention of "process of elimination" I was going to disconnect one light at a time until I could get the amps to go back to norm. I figured maybe a bad light was causing the over amperage. Or a loose joint. But remember, the JBs are located inside the storage buildings and only the one renting it can gain access to it.
Well when I had my partner turn on the breaker , it held. only 15 amps were being pulled. Hrmm I though. I took out my circular saw and plugged it into the outlet. When I turned on the saw the wallpacks on the same building and the one downstream went out. then they came back on.
I still figure loose joint to be causing this, although I have never ran across this before.
Circuits can over amp due to a loose joint somewhere?
Storage company. One of these places where people go rent, store things, ect. Rows of buildings with pull down doors.
OK. These building have wall pack lights on them. Metal Halide (sp)
1 20 amp circuit fed with #10 (for voltage drop) thhn, underground in pvc.
1 circuit feeds 3 buildings with a total of 8 100 watt fixtures per.
The conduit is run underground. It comes up into the building to a JB located on one of the corner storage areas facing inside. conduit then leaves this JB , goes back underground to feed the next building. then the third. From the JB inside each building it feed through a conduit run to a central JB which then braches off to any light located on the building. There is also one convienant outlet on the middle building.
Last week I got a call that the breaker was tripping. I checked with an amp clamp and the circuit was pulling 40+ amps. This is causing the trip.
Customer tells me the a worker plugged a circular saw into the outlet on the building and when he used it, this cause the breaker to trip and it has been doing this since. I replaced the GFI just to be sure. It was on a dead end just FYI.
I did not have time to finish that day so I re scheduled for today. I go back out with the intention of "process of elimination" I was going to disconnect one light at a time until I could get the amps to go back to norm. I figured maybe a bad light was causing the over amperage. Or a loose joint. But remember, the JBs are located inside the storage buildings and only the one renting it can gain access to it.
Well when I had my partner turn on the breaker , it held. only 15 amps were being pulled. Hrmm I though. I took out my circular saw and plugged it into the outlet. When I turned on the saw the wallpacks on the same building and the one downstream went out. then they came back on.
I still figure loose joint to be causing this, although I have never ran across this before.
Circuits can over amp due to a loose joint somewhere?
