Additional rooms, additional power.

[NanLaew]

We are currently adding a 3-bedroom annex on the back of the property that will need power.

 

The layout below shows in green and solid lines what is already in place and red and dashed lines what is proposed.

 

My first question is will we need to upgrade our current single-phase 15(45)A electrical service that serves the green bits to 30(100) A to support the new red bits?

 

What size wire from the main wall mounted breaker box, via conduit along the wall and up pole #2 (about 20 m) and wire-in-air to pole #3 to the annex (about 25 m)?

 

I will be using Schneider CU and fittings for the annex, same as I used for the office/workshop (man cave).

 

What size should the main breaker/RCBO be for the annex?

 

I plan on each room having its own 10A (lights), 16A (outlets) and 20A (aircon) service.

 

What size/type breaker for the 3200 W hot water shower units?

 

PS: (Non-electrical) we have already upgraded the water pump system, so that should manage to feed the 3 new bathrooms.

 

Thanks in advance.

 

[OneMoreFarang]

1 hour ago, NanLaew said:

What size should the main breaker/RCBO be for the annex?

 

I plan on each room having its own 10A (lights), 16A (outlets) and 20A (aircon) service.

 

What size/type breaker for the 3200 W hot water shower units?

 

You should select breakers according to the cable size. The idea is that the breaker disconnects before the cable gets too hot.

For a 3200W shower you need 3200W/230V = 13.9A. For that a 2.5sqmm cable is fine. And for that cable, and the load, a 16A breaker is fine.

Most modern AC need less than 10A. Look in the manual what they recommend (or the W and divide it by 230V).

 

There are lots of good videos on YouTube which explain about MCBs, RCCBs, RCBOs, and Amps and cable sizes.