MCB C63 vs 60 Amp Isolation Switch

[Cashboy]

I am about to wire up the house in Thailand

 

I shall have a Thai 15 (45) 1 Phase supply from the government.

I gather that I should use 16 mm2 copper or 25mm2 aluminium cables from the government meter?

I gather the cable from the earth rod should be 16mm2 copper?

 

I worry about drawing out too much power.

I understand that Thai 15 (45) should use switch gear for 63 Amp loading.

 

To protect overloading as I do not see nay in Thailand and seen two houses burn down in the village due to overloading the electrics want to install some sort of safety.

In the UK, we often use an fused isolation switch as here:

That has a 60 Amp Cartridge fuse in it.

 

But recently I bought one of these 63Amp MCB  Type C63

 

What is the difference and which one is better to use for the mains supply coming in?

 

 

 

 

 

[tjo o tjim]

Important to remember that your house load determines the current on the line, not the circuit breaker.  Larger wire will not make your house draw more power; it will have a minimal effect at reducing the load with less voltage drop.

 

The correct wire size needs to take into account distance from the meter to your home.  60A vs 63A is really just a matter of the construction specifications; either will work fine, although fuses are used less commonly here for this application.  You should however have an RCD main at the house; not sure if this is intended to be at the meter or house.  Usually your neutral-ground bond is done at the house, although US regs would require one at the first disconnect if it is outside away from the house, and a second one at the home.  This can make the RCD installation less reliable though if it isn’t done properly.

[Crossy]

Using the 63A MCB on the incoming supply will be fine, same arrangement here.

 

We added a Chang disconnector (big knife switch) to the incoming supply as I like to know everything is well and truly off before poking my fingers around.

 

Important note:- If you don't yet have a permanent meter the PEA/MEA inspector may not like the 63A breaker, just swap it for a 50A until he's been.

 

How far is it from the meter to the house? You may need to up the size of your supply cables.

 

[Cashboy]

On 12/6/2019 at 11:23 PM, Crossy said:

Using the 63A MCB on the incoming supply will be fine, same arrangement here.

 

We added a Chang disconnector (big knife switch) to the incoming supply as I like to know everything is well and truly off before poking my fingers around.

 

Important note:- If you don't yet have a permanent meter the PEA/MEA inspector may not like the 63A breaker, just swap it for a 50A until he's been.

 

How far is it from the meter to the house? You may need to up the size of your supply cables.

 

 

The distance from the government meter up the pole (5 m); from pole to roof of the house (12m): inside of the roof to a 100 Amp Mains switch (3m) so total distance 20 meters.

I therefore imagine that the 25 mm2 aluminium cable is sufficient for that.

 

After the 100 Amp Mains switch I intend to run 16mm copper to a 6 module steel box with a 125 Amp changeover switch (Government Mains / Supply from a possible generator) and the 63 Amp MCB.

 

 

And from the 63 Amp MCB go to two Consumer Units.