We installed a new small air con in one of the rooms. We already have a big one in the lounge room.

This morning the new air con is working but the others are not and some of the lights not working.

We checked the mains box on the wall inside the lounge room and all the switches are at the 'on' position.

What do you think could be the problem?

Do you have 3-phase? Could be a phase lost.

Also, click each breaker to the off position and then back to on just in case one has tripped and the lever hasn't dropped down.

If you're not sure what you have, post a photo of your breaker box and meter if you can see it.

Dropped a circuit out, surely

By conecting the new aico to the housenet maybe one the workers forgot to reconnect properly one of the wires going to the lounge from the mainbox.

Seems you have a lost of power to the lounge.

Contact the firm who install the airco and ask the electrcien worker to repair.

here is pic of our electrical panel

Thanks for the piccie.

OK, you're not on 3-phase, so it's not a phase drop. Have you tried turning each breaker off and on again in-turn to ensure none have dropped out but not dropped the toggle?

If you find no problem it's possible that the installer disturbed something in the box (he did have the lid off didn't he?), in that case I would call him back and get him to rectify.

ghworker2010, no followup post?

So, was it a lose wire, or a lose breaker.

I'm going for borrowed neutral, and in doing so dropped out the connections to other equipment ; )

what is the brand ?

in our new house, strange daikin... have to switch off main and reput

never had with our mitsubishi

It must be a connection somewhere that has disconnected during the installation of the new air-condition unit. It may have been loose before but only disconnected completely when the air-con installer messed with the electrical system/cables. Should call an "electrician" to check the problem or the air-con company that installed it.

And it could be a case of "borrowed neutral" where the installer of the air-con took a neutral from another circuit so that circuit has phase but no longer any neutral.

The problem is a disconnected cable/cables or loose conection. Thai amateur electricians do not use proper connection boxes, they just twist the wires together and hope for the best.

It must be a connection somewhere that has disconnected during the installation of the new air-condition unit. It may have been loose before but only disconnected completely when the air-con installer messed with the electrical system/cables. Should call an "electrician" to check the problem or the air-con company that installed it.

And it could be a case of "borrowed neutral" where the installer of the air-con took a neutral from another circuit so that circuit has phase but no longer any neutral.

You did not read post 4.

The problem is a disconnected cable/cables or loose conection. Thai amateur electricians do not use proper connection boxes, they just twist the wires together and hope for the best.

Read post 4 please

What does post #4 have to do with the OP? Uhm, nothing.

What does post #4 have to do with the OP? Uhm, nothing.

Post #4 has everything to do with it!

A golden rule that I applied during 40 years of electrical/electronic engineering was this. 'If fault develops following work on a circuit, go straight back and retrace your steps'. BFerearntk is correct. The onus is on the installers to come back and correct their mistake.

There will, of course be denial, there always is, but kick their butts 'til they fix it.

Thanks for sticking to you guns BFerearntk .

Sometimes, when a breaker pops open it physically doesn't look like it is in a tripped position. So switching each one off, then on again, is a good suggestion.

Next step would be to test for a defective breaker.

If you don't have a meter, or a 'tester ' screwdriver, you need to get an electrician in. If you feel confident yourself, you could take the cover off the breaker panel and physically test each

breaker for a live output.

This will give you an opportunity to check all the wires are secure... including the returns/neutrals which should run to a common bar.

Did the installer put in a new breaker and run dedicated wires for this new AC?

If not I suspect he tapped in somewhere ...maybe just onto some wiring that was 'handy', and the connection (which likely is simply a twist together of the solid core wires, is not sound.

Nor would the protection be suitable.......

You need to get a good electrician in if you cannot resolve it, I worry getting the original guy back may not help, some just do not understand what they are doing.

Good one Jacko ^^^.

I wonder why our OP has not returned, he's still active on the forums so at least he's not been zapped.