Air Conditioner Voltage Drop

There is a fault in the supply system that wants eliminating before the unit is switched on again, due to risk of fire; this is a safety issue that wants addressing as the top priority.

PWSlack is right - you have a serious and potentially very dangerous problem.

What does the A/C unit rating plate give as the KVA for the unit? Is this an industrial unit? Even with a domestic system, if the correct wiring is being used you must be drawing somewhere over 100A to get anywhere near that voltage drop. Do you have any fuses in there???!!!

Two possibilities that I can think of:

• Your cable is way too small for your AC - probably not but I've seen stranger things in my lifetime.
• You have a high resistance along your cable - this is probably more likely. You've got a connection that has carbon deposits on it or a loose connection. The connection allows enough current for you to measure the voltage but the resistance drops the voltage when more current (such as when the AC is switched on) passes through it.

The most likely place for this is at the breaker or fuse box but it can be anywhere there is a wire-to-terminal connection.

Note: if you're not a qualified electrician (and you are obviously not qualified), better hire someone to fix it.

regards,

Vulcan

I guess there is a fault in your air cond component or your air cond rated voltage is not rated at 220V. It is strange that, when you switch "ON" your Air Cond, your voltage drop from 220V to 130V which about 60% of the voltage drop.

This 60% of voltage drop is something that you have to beware and do not switch "on" your air cond until it get checked and repaired.

What you can do is to measure the voltage at the air cond terminal by removing out the air cond wire from the terminal to see if there is any problem with your cable and your connection.You should get 220V at the terminal (incoming cable.)

But this has to be done by an electrician. If you are not an electrician, please don't do it. It is very dangerous. Get expert to do it for you.