Breaker/Box Circuit Loads

[nigelforbes]

We're shortly going to instal a water tank pump at MiL's house, this has led us to examine how the current breaker box is configured in order to grab a circuit for the pump. (we're not going to do the work but we want to understand the required conguration so we can monitor the sparky). 

 

It's a small two level house with only a couple of occupants. The Safety-T-Cut consumer unit was installed 17 years ago and contains six breakers. The Sparky spread the load at the time across all breakers, this was not optimal because it means one breaker has only only a single light and socket. At present, one breaker is spare but the remaining configuration is cause for concern, because of the ad-hoc bolt ons that have magically appeared over time! Ideally we need to reconfugure the consumer unit, this is what I think it probably should look like but will appreciate any guidance:

 

B1 - Upstairs lights/sockets - perhaps 10 lights and 6 sockets, no heavy load devices (It would be optimal to split these across two breakers but that means buying a new consumer unit).

B2 - Upstairs Bathroom water heater

B3 - Underhouse lights and sockets - perhaps five lights and three sockets, no heavy load devices

B4 - Downstairs Water Pump (150 watt) plus washing machine power point.

B5 - Kitchen - Refrigerator, light and socket - no heavies

B6 - small shop - refrigerator, light, fan

 

Seem reasonable?

Edited May 13, 2023 by nigelforbes
correct spelling errors

[cnx1204]

Breaker box has no expansion slots?  

 

You might add what is the rating of each breaker to make it easier for a knowledgeable person to offer advice.  I am not that person, but I had to double the amps to handle new loads for a couple of breakers in my house a long time ago.

[KannikaP]

Seems OK to me. My 4 bedroom house from 2012, was wired with just 4 x 20 amp breakers, running (not all at the same time), 4 x ACs, 2 x 3kW showers, 3 x fridges, 3 x TVs, 2 x PCs, many LED lights, washing machine, water pump and a few fans. Never had a cut-out ever.

[nigelforbes]

11 minutes ago, cnx1204 said:

Breaker box has no expansion slots?  

 

You might add what is the rating of each breaker to make it easier for a knowledgeable person to offer advice.  I am not that person, but I had to double the amps to handle new loads for a couple of breakers in my house a long time ago.

No, it's a six breaker box, that's it.

 

A good point about the breaker capacity but I don't have that info to hand.

[nigelforbes]

13 minutes ago, KannikaP said:

Seems OK to me. My 4 bedroom house from 2012, was wired with just 4 x 20 amp breakers, running (not all at the same time), 4 x ACs, 2 x 3kW showers, 3 x fridges, 3 x TVs, 2 x PCs, many LED lights, washing machine, water pump and a few fans. Never had a cut-out ever.

We went from 10 breakers to 18 and we're now out of slots but almost anything with any pulling power has it's own home. But we're running 3 outside pumps, five air con, three 6k water heaters. electric gates, plus the usual stuff.

[sometimewoodworker]

2 hours ago, nigelforbes said:

It would be optimal to split these across two breakers but that means buying a new consumer unit

The consumer unit boxes are neither expensive nor difficult to fit you can find a small one with breakers for around 500 Baht. There is no need to replace the one you have, just add another one.

Edited May 13, 2023 by sometimewoodworker

[bluejets]

Light and power outlets are not normally wired on the same circuit, unless it is a "mixed circuit" and has cabling not less than 2.5 sq mm and run on maximum of 20A circuit breaker. If yours is covered by this then you are ok.

 

Normal arrangement is lighting on a 1.5 sq mm cabling protected by a 10A RCBO and power outlets on 2.5 sq mm cabling protected by a 20A RCBO, all with 30mA trip level and using the newer "Type A, F or B......... Type AC is now out in many countries)

 

Example .............. https://www.worksafe.qld.gov.au/news-and-events/newsletters/esafe-newsletters/esafe-editions/esafe-electrical/2023-newsletters/february-2023/type-ac-rcds-banned-from-30-april-2023#:~:text=Electrical contractors must not install,no exemptions for existing projects.

 

And here.......... https://www.worksafe.qld.gov.au/news-and-events/newsletters/esafe-newsletters/esafe-editions/esafe-electrical/2020-bulletins/choose-the-right-safety-switch-for-the-job

 

It is more appropriate these days to run each circuit on it's own safety cut device (commonly known as a combo) which has both the circuit breaker and the earth leakage component in the one unit, RCBO.

Reason is obvious, when it comes to any earth leakage fault, only that circuit's RCBO combo will trip, retaining your other lights and points.

Edited May 16, 2023 by bluejets

[Encid]

Whilst on the subject of breaker sizing, I have a related question about cable sizing.

 

We are about to start the electrical wiring of our new house build in Isaan.

 

I have read that wire size AWG 18 is good for 10A or current, AWG 14 is good for 15A, AWG 12 is good for 20A, and AWG 10 is good for 30A.

 

 

The problem is that most Thai electricians use only one sized wire throughout the entire house unless told otherwise.

 

So I am thinking that apart from the circuits for the water heater (6000W therefore 30A wiring required) and the air conditioning units, I could have the rest of our new house wired in AWG 12 (20A) for all the power circuits, and AWG 14 (15A)for the lighting circuits.

 

We have no plans for an electric oven so that is not on our consumers list.

 

Thoughts/comment please?

[sometimewoodworker]

1 hour ago, Encid said:

Thoughts/comment please?

The information you are quoting is mostly irrelevant in Thailand as Thailand does not use the American Wire Gage and you haven’t given enough details either.
 

If you want comments from the majority of people here you should use the standard messaging system used in the majority of the world which is the metric system. There are a few who know the conversions and will probably comment. You have the conversions in your post, using the standard is polite.

 

2 hours ago, Encid said:

The problem is that most Thai electricians use only one sized wire throughout the entire house unless told otherwise.

There are vanishingly few Thai electricians working on houses so they will use the standard size of 2.5mm unless told otherwise, this is a perfectly sensible approach. You know the loads your system will carry, if you don’t know the sensible wire sizes people will be happily to assist. If you have an actual qualified Thai electrician he will be more than capable of assessing your needs.

 

The wire sizes are dependent on the installation method, that is probably the main reason you see wiring clipped to walls here as that gives the greatest load carrying capacity. Put in conduit and the load limit drops, put in concrete and it drops again. 
FWIW (not much) I have about 42 9W LEDs on either 0.75mm (or 1mm. IDR) 

[bluejets]

 

4 hours ago, Encid said:

Whilst on the subject of breaker sizing, I have a related question about cable sizing.

Depends.......aluminium or copper........???

Most would assume copper............so.......

Usual accepted rating (again depends on how it is installed) however ..........

1 sq mm ..........generally 10A.

Most tend to use 1.5 though for lighting and protect with 10A RCBO combo

2.5sq mm for power....again generally 20A but rating can go to 28A...16A RCBO

Any 15A point we tend to use 4 sq mm and 20A RCBO.

4.0 sq mm ....32A max.

6.0sq mm .....around the 40A mark

 

Above does not take voltage drop into account ........

 

 

[Muhendis]

13 hours ago, Encid said:

Whilst on the subject of breaker sizing, I have a related question about cable sizing.

 

We are about to start the electrical wiring of our new house build in Isaan.

 

I have read that wire size AWG 18 is good for 10A or current, AWG 14 is good for 15A, AWG 12 is good for 20A, and AWG 10 is good for 30A.

 

 

The problem is that most Thai electricians use only one sized wire throughout the entire house unless told otherwise.

 

So I am thinking that apart from the circuits for the water heater (6000W therefore 30A wiring required) and the air conditioning units, I could have the rest of our new house wired in AWG 12 (20A) for all the power circuits, and AWG 14 (15A)for the lighting circuits.

 

We have no plans for an electric oven so that is not on our consumers list.

 

Thoughts/comment please?

The sizes of 4mm and 2.5 mm ( AWG 12 and AWG 14) are fine.