I've been doing this stuff for years and today this one kind of threw me for a loop.
Existing install, very bad install actually. Originally put in a few years back with 8 gauge 3 conductor, no earth ground wire. 70-100 foot run underground with conduit to back shed. :-(
Source (house) panel input is L1, L2, and EG/N tied together. EG/N buss is bonded together. Ok fine.
At the back shed, L1, L2, and incoming N lines are isolated. There was no bonding in the shed box. Shed box has EG buss separate, isolated from Neutral buss. EG wire runs outside of box into buried solid copper outside.
From here, 0 gauge (I may be wrong on gauge, but it's definitely big ugly stuff that I hate to deal with) aluminum wiring going another 50+ feet to a pool box with breakers. 4 wires. L1, L2, N, and a G. (Pool electrician was obviously trying to do his job right).
This box is wired with isolated neutral and EG - (No bonding).
I AM getting some current flow between the buried EG wire and the EG buss in the box, it's minute, and I didn't measure the voltage. I'm going back tomorrow and will do this (carefully). Anyway, earth ground (rod) is attached at the shed now.
Everything works. However, it seemed odd that neutral and EG were isolated way out there as there was no way to properly return a ground fault since no separate EG was run from the house.
So I bonded the neutral at the box to the EG and then nothing works. The breakers trip immediately. Well except for the pool light which has a maximum current draw of about 3 amps (250 w/120v) (and it's on a working GFI which doesn't trip).
1 pump is running 230, other pump is running 115. Either pump trips BOTH the shed 40 amp breaker and the associated pump breaker instantaneously with the bonding in place.
I'm beginning to think that both pumps have a ground fault... but this seems really weird though. Any ideas anyone?
Existing install, very bad install actually. Originally put in a few years back with 8 gauge 3 conductor, no earth ground wire. 70-100 foot run underground with conduit to back shed. :-(
Source (house) panel input is L1, L2, and EG/N tied together. EG/N buss is bonded together. Ok fine.
At the back shed, L1, L2, and incoming N lines are isolated. There was no bonding in the shed box. Shed box has EG buss separate, isolated from Neutral buss. EG wire runs outside of box into buried solid copper outside.
From here, 0 gauge (I may be wrong on gauge, but it's definitely big ugly stuff that I hate to deal with) aluminum wiring going another 50+ feet to a pool box with breakers. 4 wires. L1, L2, N, and a G. (Pool electrician was obviously trying to do his job right).
This box is wired with isolated neutral and EG - (No bonding).
I AM getting some current flow between the buried EG wire and the EG buss in the box, it's minute, and I didn't measure the voltage. I'm going back tomorrow and will do this (carefully). Anyway, earth ground (rod) is attached at the shed now.
Everything works. However, it seemed odd that neutral and EG were isolated way out there as there was no way to properly return a ground fault since no separate EG was run from the house.
So I bonded the neutral at the box to the EG and then nothing works. The breakers trip immediately. Well except for the pool light which has a maximum current draw of about 3 amps (250 w/120v) (and it's on a working GFI which doesn't trip).
1 pump is running 230, other pump is running 115. Either pump trips BOTH the shed 40 amp breaker and the associated pump breaker instantaneously with the bonding in place.
I'm beginning to think that both pumps have a ground fault... but this seems really weird though. Any ideas anyone?
