Voltage reading at 180V after commissioning.

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KevinKos

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Arlington, TX, USA
Hello y'all.

My question might be a very basic question. But I need some education.

I installed 35 hanwha 290 watt Mono with Enphase m250 on a residential house.

used 10/4 wire to bring the ac to the sub panels(2 x 20A breakers, 1 x 15A breakers)->60A AC disconnect -> MSP (derated from 200A to 175A) 50A PV circuit breaker.

It was a little cloudy. but i believe it's nothing to do with the voltage..

i was checking the voltage on that 50A breaker on the MSP. It was reading 180V. i found it weird.. isn't it supposed to be 240v?


sorry for the stupid question. :?

Thank you!
 
One thing I can tell you is that if that is truly the voltage then your inverters aren't going to turn on.

Verify if the service is supposed to be 240V or 208V. Where I'm from all single family homes are 240V but I've heard that some places have 208/120 single-phase. That's a low line-to-line reading for a 208V service, but maybe not so low as to cause the customer noticeable problems. Try to eliminate other potential issues (bad breaker? malfunctioning meter?), and if you determine that the utility is truly delivering an incorrect voltage then it's their obligation to fix it.
 
There’s something going on that has nothing to do with the inverters. Turn off the inverters and start tracing the voltage from the MSP. If the MSP is 240V and the new sub is 180V then you know where you need to look.
 
jaggedben said:
One thing I can tell you is that if that is truly the voltage then your inverters aren't going to turn on.

Verify if the service is supposed to be 240V or 208V. Where I'm from all single family homes are 240V but I've heard that some places have 208/120 single-phase. That's a low line-to-line reading for a 208V service, but maybe not so low as to cause the customer noticeable problems. Try to eliminate other potential issues (bad breaker? malfunctioning meter?), and if you determine that the utility is truly delivering an incorrect voltage then it's their obligation to fix it.
Click to expand...


Thank you for the detailed answer. Came to find out the voltage meter was messed up. We bought a voltage meter from the Harbor Freight...
Never thought the problem was the voltage meter...

I apologize !
 
KevinKos said:
Thank you for the detailed answer. Came to find out the voltage meter was messed up. We bought a voltage meter from the Harbor Freight...
Never thought the problem was the voltage meter...

I apologize !
Click to expand...

You are lucky all that happened was a voltage mis-read.

My advice to all is to NEVER use cheap Harbor Freight meters on live AC mains circuits. They are OK for 12 volt stuff and measuring resistance. I own several of them.

One of my friends had one BLOW UP when he was reading across a panel's 240 volt mains. Lucky for him, he only got some very minor burns and scratches from the plastic shards. If he was looking at the meter when it blew, he would have got a face full.

I saw a video Fluke did with one of the Harbor Freight meters, a red one like they sell for 5 bucks. It blew up like a bomb.

For AC mains voltages and higher, ONLY use a meter whose CAT ratings you can trust, and then only use them in the CAT areas they are rated for.
 
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