What Manufacturer Of Cu? And Other Questions.

[Mike45]

What manufacturer of CU for availability of individual protection circuits by ELCB or RCBO individual breakers?

I had assumed that no matter which brand my builders electrician chooses that I would be able to get individual breakers ELCB/ RCBO/GFCI for individual circuits. He didn't plan to use any.

I'm trying to play catch up here because I don't know how to equate what I know about circuit protection in the states to what is done here.

For example in the states a new home would install a minimum of a 100 A service or most probably today a 200 A service. The Main Circuit breaker would be either a 100A or a 200A.

Most individual lighting or power circuits would have 15A or 20A breakers. Higher ratings for a dryer, oven, Hot water tank.

Any individual circuit that was in a wet area, bathroom, kitchen, outside lamp post , outside outlet would be protected by an individual GFCI breaker.

Recently it was recommend to me to upgrade the service, before its installed, from 15A to 30A. I said yes I want it but to be honest I have no idea what I have agreed to or if I need it. Because all these numbers appear so low to me and because I believe more is better when it comes to electrical capability I agreed.

If its a choice of 15A or 30A why do many of the Main Circuit Breakers appear to be 63A?

I'm thoroughly confused.

Mike

[impulse]

For one thing, at local 220V (50Hz), the amperage is 1/2 of what it is at 110V (60Hz) to run the same watt load.

So expect common household breakers to be about 1/2 the amperage rating you'd expect back home. Oven, furnace, dryers, A/C and other loads that run at 220V in the USA are, of course, an exception and breakers would be rated similarly.

For the rest of your questions, I'd defer to a qualified electrician. I'm a mechanical guy by degree.

[Crossy]

Schneider / Square-D boards have readily available single width RCBOs (GFCI) about 1500 Baht each IIRC.

Here (as noted above) supply is 220V so the current is half what you would see in the US.

A normal 'farang' incoming supply is 15/45 which will likely be fused at 50 or 63A (equivalent to a US 100A service). This is more than adequate for a small to medium sized home, we have two 7kW water heaters and a couple of A/Cs, our 15/45 supply has never tripped even when I tried to by turning everything on.

A 30/100 (which is what your '30A' supply is) fused at 100A would do a fairly large home and is roughly equivalent to a US 200A service.

Lighting will usually be on a 10A breaker, power circuits on a 20A, A/C and water heaters on individual breakers of appropriate rating for the equipment.

[Mike45]

Schneider / Square-D boards have readily available single width RCBOs (GFCI) about 1500 Baht each IIRC.

Here (as noted above) supply is 220V so the current is half what you would see in the US.

A normal 'farang' incoming supply is 15/45 which will likely be fused at 50 or 63A (equivalent to a US 100A service). This is more than adequate for a small to medium sized home, we have two 7kW water heaters and a couple of A/Cs, our 15/45 supply has never tripped even when I tried to by turning everything on.

A 30/100 (which is what your '30A' supply is) fused at 100A would do a fairly large home and is roughly equivalent to a US 200A service.

Lighting will usually be on a 10A breaker, power circuits on a 20A, A/C and water heaters on individual breakers of appropriate rating for the equipment.

Looks like Schneider square D are the way to go.

Thanks

Crossey

[Crossy]

A word of warning. If you do decide to go the 'multiple RCBO' route rather than having a single front-end RCD or a split-service CU you'll need to keep a close eye on your sparks.

Thai electricians have an annoying habit of picking up (borrowing) any old neutral when they need one. This will lead to nuisance trips (or RCBOs that will never stay engaged) and can be a nightmare to fault find

Our new home has borrowed neutrals all over the place (I was in India when the chap did his install). Luckily we have split CUs (not individual RCBOs) so it wasn't too much of a nightmare to get working reliably but I had to do it as it was totally beyond any of the chaps we employed.

[lopburi3]

As said locally it makes more sense to use the single RCBO than in US for several reasons - cost being one - but here normally you are barefoot inside cement home and most often floors are easily conductive with water/sweat film on them so all the house is a "wet" area. Best to protect all circuits (even those that may cause issues later such as compressors in refrigerators). I have had full home protection since RCBO became available in the 1978 here and almost no issues with false trips at normal 30ma setting - below that it can be a problem). Along with the amperage don't be shocked when you see the wire size - higher voltage means much thinner wire can be used that we Americans are used to seeing.

[Mike45]

A word of warning. If you do decide to go the 'multiple RCBO' route rather than having a single front-end RCD or a split-service CU you'll need to keep a close eye on your sparks.

Thai electricians have an annoying habit of picking up (borrowing) any old neutral when they need one. This will lead to nuisance trips (or RCBOs that will never stay engaged) and can be a nightmare to fault find

Our new home has borrowed neutrals all over the place (I was in India when the chap did his install). Luckily we have split CUs (not individual RCBOs) so it wasn't too much of a nightmare to get working reliably but I had to do it as it was totally beyond any of the chaps we employed.

Crossey

I read your site about split CU but wasn't really sure why it was needed.

If I use a RCBO Main Circuit Breaker instead of individuals will I be properly protected? Maybe that's the best way to go. Don't know.

Mike

[Mike45]

As said locally it makes more sense to use the single RCBO than in US for several reasons - cost being one - but here normally you are barefoot inside cement home and most often floors are easily conductive with water/sweat film on them so all the house is a "wet" area. Best to protect all circuits (even those that may cause issues later such as compressors in refrigerators). I have had full home protection since RCBO became available in the 1978 here and almost no issues with false trips at normal 30ma setting - below that it can be a problem). Along with the amperage don't be shocked when you see the wire size - higher voltage means much thinner wire can be used that we Americans are used to seeing.

That's a valid point I hadn't considered.

What manufacturer do you have? What do you mean by 30ma setting? I didn't see any of the devices that were adjustable.

Thanks

[lopburi3]

Safe-T-Cut was the first unit available here (actually made here) and has always had adjustment from about 5ma to 30ma and bypass mode available on most units. I currently still have that original unit (1977-8) and on several additional panels have Oz made Clipsal panel mount units which are the normal 30ma.

[sirineou]

Great Thread

Thank;s the OP for starting it and all the Great responses

I was also wondering about the low AMP cb's and service boxes, but never asked the question

Some tines the obvious eludes you

The answers in this Thread are eloquent in their simplicity,

. according to Ohm's law since the Voltage is higher is higher it requires less wattage to overcome a particular resistance.

but I am humbled to say that I never thought of that answer

Let me say it again Great Thread ,