Roof AC Tripping Generator 30 AMP 20 AMP OK

[lsbrodsky]

Originally Posted by kpm

Could you give an link to a decent one online?

https://www.amazon.com/Amprobe-ELS2A...8-c6d731c47e82

Larry

[hotfoot88]

Maybe there is more load on 30 amp than just AC

[kpm]

Originally Posted by lsbrodsky

https://www.amazon.com/Amprobe-ELS2A...8-c6d731c47e82

Larry

Looks well worth the price. Thanks.

[92landyacht]

Originally Posted by kpm

Looks well worth the price. Thanks.

Wont do a lot for troubleshooting the generator issue though.

[1956elli]

Per my meter checking the same wall plug - I get 121V on shore power and 118 of gen

Will do amp test tomorrow - been advised by boss I have stuff to do elsewhere

I will ask - since I do not know - if AC trips 30A on generator - why does the 30A inside not trip while on shore power

[92landyacht]

Originally Posted by 1956elli

Per my meter checking the same wall plug - I get 121V on shore power and 118 of gen

Will do amp test tomorrow - been advised by boss I have stuff to do elsewhere

I will ask - since I do not know - if AC trips 30A on generator - why does the 30A inside not trip while on shore power

OK, so you say you have 118 with generator but is that 118 with the suspect AC on or off. If it's when off, than it's not while the generator is loaded down. Volts may drop off when loaded down. In the end it may still be a weak breaker but now you'll have the tools and know-how on what to do if you have other electrical issues. I'm assuming that the "wall plug" you testing is also on the same 30 amp circuit as the front AC.

[bkahler]

Originally Posted by 92landyacht

OK, so you say you have 118 with generator but is that 118 with the suspect AC on or off. If it's when off, than it's not while the generator is loaded down. Volts may drop off when loaded down. In the end it may still be a weak breaker but now you'll have the tools and know-how on what to do if you have other electrical issues. I'm assuming that the "wall plug" you testing is also on the same 30 amp circuit as the front AC.

As the generator voltage drops during load with the AC running the amperage goes up. So if you're running on shore power and the voltage is 120 volts your current is probably around 13 amps. If you're on generator power and your voltage starts at 118 with no load and you start the AC then the voltage most certainly will drop, possibly as low as 108 volts and your current climbs. That's most likely what is causing the breaker to trip.

Most roof top AC units draw between 12 and 15 amps when running.

[1956elli]

Hay guys - THANKS for all the info - more testing tomorrow

As 1 has mentioned "having tools and know how" got 1/2 of that - tools

[guskmg]

Almost everything has been covered here. Feel all the connections, plugs, sockets. even the circuit breaker(s). If any feel hot, that is your problem. A poor connection is like adding a heater in the circuit. The amps go up and the breaker pops. Use a laser heat detector to avoid getting burned.
guskmg

[uncle_bob]

Hi

In terms of "why does this happen?" ... well, it should not happen. Something somewhere is wrong. It could be multiple things at the same time. The only way to sort that out is to take the basic data and see if that helps. If things are still unclear *with* further data, you simply start replacing everything. Breaker comes first, then the connectors, then the cords, and on it goes .....

Bob

[mayco]

More testing needed to troubleshoot but I'm with UncleBob on the possibility of a bad breaker on the generator. Breakers can get weak over time and can be bad out of the box.
We are all guessing at this point but sure sounds like a good place to start, the symptoms sound like a bad breaker on the genny. BUT!!! Could be several other things too, more testing is needed. If it is a bad breaker, you're lucky, cheap and easy fix.

[1956elli]

Again thanks for all info

Gona start with new 30AMP next week only reason being the same ac unit does not trip the inside 20AMP when on shore power

Will provide updates as I go

Last test - Shore power 121V inside with AC on - 116V inside same place while on generator AC on before 30AMP trips approx. 6 min

[mayco]

The generator voltage is about the same as mine with one ac running. I might see 117.
When I start the second ac while on generator it will dip down to 108-110 at start up but then settles in at about 111. I've only run both ac units on generator to see how the generator would function but don't make it a practice. Never had a breaker trip on the genny.

[1956elli]

Well - it was a bad 30AMP breaker

Replaced it made a 4 day run out in west Texas, was about 103 each day, both AC's ran no problem

[rowiebowie]

Originally Posted by 1956elli

Well - it was a bad 30AMP breaker

Replaced it made a 4 day run out in west Texas, was about 103 each day, both AC's ran no problem

Thanks for posting the update. Not everyone comes back to post their solution. And glad you didn't bake (easy to do in a Texas Summer).