So, I went to fire up the pool pump yesterday (a daily occurrence, not on a timer) and the ground fault protection tripped and wouldn't reset.
No problem - only two possible issues - one, a real fault (unlikely, this is indoors, fairly new, and a pretty clean situation overall) or the GFCI has given up. This is where things start to get interesting.
The pump is 3/4 HP, so it should draw ~11 amps - totally fine for the 120V circuit it seems to be on. There is a nice light switch by the boiler room door, which feeds one of these: http://www.homedepot.com/catalog/productImages/1000/d2/d222cd2a-26e3-46ad-b9d0-fb568da17e76_1000.jpg, and then feeds the pump. A bit of a pain, since the GFCI won't pull in unless it has power, so the switch has to be on to reset it, but not a problem.
So I pick up a new GFCI, come home, kill the breaker for the pump and for the adjacent boiler circulating pump, remove the cover and start extracting the old GFCI.
This is where the tingly surprise happens - and I know better, I should have tested the wires before getting into them, I was in a rush and didn't go hunting for my tester. But of course, here is the real puzzle - why is there 121V on the hot lead on the GFCI? Well, it turns out that another circuit on the other phase seems to feed that - the circuit for the water softener.
After some sleuthing, turning off the correct pair of breakers, replacing the GFCI, and turning it on again, I'm left with 240V across the supply to the pump - which wouldn't be unusual, were it not for the fact that everything seemed to be set up for 120/115. The pump again works, but now I have an issue.
This leaves me with a schematic diagram (excuse the lack of artistry) and some points / questions:
[Breaker 5] -------------------------- |GFCI| ----- |Pump|
[Breaker 8] ----- [Light Switch] ----- |****| ----- |****|
P1) Obviously this is very wrong, and unsafe.
P2) The GFCI is rated at 20A for 120V (not rated for 240V)
P3) My load center is obsolete, and finding a GFCI breakers is not possible.
P4) At 5.5A for 240V, and 11A for 120V, the existing wiring can handle the anticipated current.
Q1) Is there any issue with converting down to 120V and continuing to use the Light Switch and GFCI driven by only a single breaker?
Q2) How could anybody ever wire this up and think it was a good idea? This seems completely bizarre - this is actually more difficult than just wiring up for 120V.
Q3) Am I missing anything? Should I take another course of action? I'm not an electrician, but I am an engineer.
Your thoughts appreciated!
No problem - only two possible issues - one, a real fault (unlikely, this is indoors, fairly new, and a pretty clean situation overall) or the GFCI has given up. This is where things start to get interesting.
The pump is 3/4 HP, so it should draw ~11 amps - totally fine for the 120V circuit it seems to be on. There is a nice light switch by the boiler room door, which feeds one of these: http://www.homedepot.com/catalog/productImages/1000/d2/d222cd2a-26e3-46ad-b9d0-fb568da17e76_1000.jpg, and then feeds the pump. A bit of a pain, since the GFCI won't pull in unless it has power, so the switch has to be on to reset it, but not a problem.
So I pick up a new GFCI, come home, kill the breaker for the pump and for the adjacent boiler circulating pump, remove the cover and start extracting the old GFCI.
This is where the tingly surprise happens - and I know better, I should have tested the wires before getting into them, I was in a rush and didn't go hunting for my tester. But of course, here is the real puzzle - why is there 121V on the hot lead on the GFCI? Well, it turns out that another circuit on the other phase seems to feed that - the circuit for the water softener.
After some sleuthing, turning off the correct pair of breakers, replacing the GFCI, and turning it on again, I'm left with 240V across the supply to the pump - which wouldn't be unusual, were it not for the fact that everything seemed to be set up for 120/115. The pump again works, but now I have an issue.
This leaves me with a schematic diagram (excuse the lack of artistry) and some points / questions:
[Breaker 5] -------------------------- |GFCI| ----- |Pump|
[Breaker 8] ----- [Light Switch] ----- |****| ----- |****|
P1) Obviously this is very wrong, and unsafe.
P2) The GFCI is rated at 20A for 120V (not rated for 240V)
P3) My load center is obsolete, and finding a GFCI breakers is not possible.
P4) At 5.5A for 240V, and 11A for 120V, the existing wiring can handle the anticipated current.
Q1) Is there any issue with converting down to 120V and continuing to use the Light Switch and GFCI driven by only a single breaker?
Q2) How could anybody ever wire this up and think it was a good idea? This seems completely bizarre - this is actually more difficult than just wiring up for 120V.
Q3) Am I missing anything? Should I take another course of action? I'm not an electrician, but I am an engineer.
Your thoughts appreciated!