n2aws
Solar Addict
- Joined
- Oct 24, 2022
- Messages
- 681
Hey all,
I thought I had a pretty solid understanding of "split-phase 240v", grounds and neutrals, bonding.. etc.
However, about 2 months ago, my father in law had an issue I tried to help him with. First, the TL;DR, and then more details:
From the utility, I saw 120v on L1. I also saw 120v on L2. However, between L1 and L2, I saw 17v.
The longer version: FIL knows I've been doing a DIY solar build. He called me up saying that all the lights, refrigerators, etc worked in his house.. but his well pump, Central A/C, and oven weren't working.
Even before I got to his house, I suspected it was something to do with the 240v, and maybe one of the "hots" was dead, allowing some 120v stuff to work, but not 240v.
I get to his house, and break out the multimeter. After tracing the problem up (started at his subpanel with those loads). it turns out that on the mains into his main panel, I saw full voltage on *either* leg to ground. But when testing hot to hot, it was 17v.
He called the utility, and they dispatched a crew. A little later, the next door neighbor called and asked him if he had power. Turns out, they were having the same issue. Utility came out, and I told the guy who I saw first what troubleshooting I had done. He simply said "Hmm, sounds like a hot is burned out somewhere" but gave no further explanation. I left before they really got started (I had other plans, and needed to go)
It's been almost 2 months. They have not fixed whatever the original problem was, but instead, ran "temporary" wiring that is just laying on the ground in his driveway, from the transformer on a nearby pole.. to his meter box. Its a good thing they were able to do the temporary wiring though, cuz 2 months without A/C or water would be horrible anywhere, but especially in florida summer.
So, how the heck do 2 legs that seem to test ok at 120v each, result in 17v between them. is this an "out of phase" scenario?
I thought I had a pretty solid understanding of "split-phase 240v", grounds and neutrals, bonding.. etc.
However, about 2 months ago, my father in law had an issue I tried to help him with. First, the TL;DR, and then more details:
From the utility, I saw 120v on L1. I also saw 120v on L2. However, between L1 and L2, I saw 17v.
The longer version: FIL knows I've been doing a DIY solar build. He called me up saying that all the lights, refrigerators, etc worked in his house.. but his well pump, Central A/C, and oven weren't working.
Even before I got to his house, I suspected it was something to do with the 240v, and maybe one of the "hots" was dead, allowing some 120v stuff to work, but not 240v.
I get to his house, and break out the multimeter. After tracing the problem up (started at his subpanel with those loads). it turns out that on the mains into his main panel, I saw full voltage on *either* leg to ground. But when testing hot to hot, it was 17v.
He called the utility, and they dispatched a crew. A little later, the next door neighbor called and asked him if he had power. Turns out, they were having the same issue. Utility came out, and I told the guy who I saw first what troubleshooting I had done. He simply said "Hmm, sounds like a hot is burned out somewhere" but gave no further explanation. I left before they really got started (I had other plans, and needed to go)
It's been almost 2 months. They have not fixed whatever the original problem was, but instead, ran "temporary" wiring that is just laying on the ground in his driveway, from the transformer on a nearby pole.. to his meter box. Its a good thing they were able to do the temporary wiring though, cuz 2 months without A/C or water would be horrible anywhere, but especially in florida summer.
So, how the heck do 2 legs that seem to test ok at 120v each, result in 17v between them. is this an "out of phase" scenario?
