Thread: A/C and wiring gauge thickness?

Even 15 amp is to low for the mtr but most soys around me have only 16mm cable along the soy .
I wanted 35mm cable to the house because of the AC but was told why as the soy is 16mm .
Well all my lights are low wt consumtion and 4 AC units but only 2 are used at a time mostly.
Bigest problem we have is the volt drop at peek times 220vac can drop to 190vac , this can be bad for AC units but we have had luck so far no problems in 10 yrs in the house .
Oh we have volt and amp meters on the main panel.

Originally Posted by dirtydog

Originally Posted by liveinlos

The standard Thai electric meter on the pole outside of your house is only 5 amps.

HUH? You spying on him?

Originally Posted by liveinlos

12 gage wiring can handle 20 amps 10 gage wiring can handle 30 amps 8 gage wiring can handle 50 amps (3) 6 gage wires in a conduit will safely handle 65 starting amps

This isn't Thai wire for Thailand I take it?

Yes i think its American speak and will be based on 120vac.

Originally Posted by liveinlos

The standard Thai electric meter on the pole outside of your house is only 5 amps. You will need to have this upgraded to 15 amps to run multiple air cons at the same time. You will also need to install a circuit breaker for each air conditioner unit in the house.

Wire size needs to be calculated for load draw or the amount of electricity at start up. Air cons typically draw around 65 amps but it can be more depending on the size of the air con.

Copper wire is the preference for electrical motors

Here are some simple formulas

Amps = Watts / Voltage

1 BTU = 0.2930711 Watt-Hour

12 gage wiring can handle 20 amps

10 gage wiring can handle 30 amps

8 gage wiring can handle 50 amps

(3) 6 gage wires in a conduit will safely handle 65 starting amps

With wiring, it is best to have oversized and not marginal size.

The current draw of two units may be higher than the current draw of one unit resulting in a higher electric bill. You need to research the continuous amp draw for the (2) units (add the amps together) versus the continuous amp draw of the larger unit to see which one uses the least amount of amps.

The start up current draw is greater than the continous operating draw

Wiring has to handle the start up load most importantly

Another issue to consider is the size of the outside electric meter.

You want to make sure if you are running multiple A/C's, hot water heaters, clothes dryer, microwaves or ovens at the same time that they are not using combined amps greater than your outside meter.

The Air Con's need their own circuit breaker separate from the wall socket wiring.

I have found most local air con shops that sell air cons will come move and rewire the air cons for you for less than 1,000 baht. In my area it was around 600 baht.

I used National Circuit Breakers inside my house. Power and ground run straight from outside into the Circuit breaker, then to the air con. The breaker has a manual shut off switch in case of overload.

One thing I have studied:

When using an 18,000 BTU air cond downstairs all day maybe 12 hours, then a 14,000 BTU upstairs at night, shutting off the downstairs unit, the electric bill jumps 3800+ THB per month from not using any air conditioning.

The standard domestic electric meter in Thailand is not 5 amps - it is 15 Amperes/ 45 Amperes loaded. - plus some of the above calculations are incorrect - i.e. Amperes= Watts/Voltage, simply not true, this only applies in a pure DC circuit - AC - i.e. your home follows a different set of rules.

5 Ampere metres are for the agricultural side of things and I believe are tax free. (I know, I was fined for using the 5 Ampere job to supply my house)

The other option may be to look at 3 phase, putting your heavy current devices on one or two of the phases and the rest of your normal lighting etc. on the third phase.