How to add extra house circuits?

[HTC]

I have a Schneider Square D load centre with 18 circuits.

 

I'm fitting a swimming pool and garden lighting, but have run out of circuits and I don't want to double up on things.

 

Is it possible to separately purchase the insides of these boxes to add more circuits? Seems like there are spaces in the metal case.

 

Is it a big job to change the load centre?

[Crossy]

Check with you local electrical emporium (not Homepro or the like, a proper electrical specialist), you certainly used to be able to get expansion kits for these load centres but I've never seen them in Thailand.

 

If not then you will need to add a small external box (or a baby load center to keep things matching) with extra breakers and (MOST IMPORTANT) some form of earth-leakage protection for your outdoor and pool circuits (you may want to add same to your water heater circuits too).

 

If you do want to just install a bigger load centre it looks like a simple job for a local sparks (not really DIY), you don't have the usual Thai spaghetti in there.

 

Personally for just external lights and the pool I would double up on a couple of low power outlet circuits (bedrooms), remove the (now spare) MCB and add a plug-in RCBO for your new stuff. Easy and reasonably cheap (and you could DIY).

 

[HTC]

Thanks for all that.

 

My sparky has advised me to go for the extra small load centre. I just wanted to have it all in one box for neatness.

 

My electrician tells me changing the large load centre is a big job although it doesn't look like it to me. I might get a second opinion on that.

 

I will head to my local electrical store (we have a large one called Supot here in Samui, so should be able to advise on parts).

 

Thanks for the tip on the extra protection for circuits involved with water. I'll check on that.

 

First option will be to keep it neat in one box, if not possible, an extra box will be ordered.

 

Btw, I'm not doing any of the work myself although I could. I don't want it on me if anything goes wrong.

 

Also, forgot to say I'm adding a sliding door opening for the driveway.

 

 

[Crossy]

12 minutes ago, Arjen said:

Crossy, I adore you. And I really do. But this sounds like "spaghetti to me" 

 

Nah, he would need to move one wire (to combine circuits), remove the MCB, stick in an RCBO and run his new circuit to it.

 

His existing board is quite neatly wired so replacing it with a bigger one with more circuits should be a relatively quick and simple task, but for just his pool and outside lights (unless he has bigger plans) I'd be looking at the cheap and simple option.

 

[Crossy]

1 hour ago, HTC said:

Also, forgot to say I'm adding a sliding door opening for the driveway.

 

From bitter ($$$) experience put some surge protection on the gate end of the power supply. We have lost two controllers and gate motors to lightning surges in the past.

 

[Rimmer]

4 minutes ago, Crossy said:

 

From bitter ($$$) experience put some surge protection on the gate end of the power supply. We have lost two controllers and gate motors to lightning surges in the past.

 

What do you use as surge protection Crossy?

[Crossy]

33 minutes ago, Rimmer said:

What do you use as surge protection Crossy?

 

We have a big whole-house surge arrestor on our incoming supply.

 

But as our gates are on a long feed from the house I bought a bag of these chaps http://www.mynpe.com/mynpe/more.php?data=116450101022 from AliExpress. Connect L-N, L-E, N-E (so 3 MOVs). If you have them in the house they should be in a metal box, but out by the gate ours are in a cheap plastic box.

 

Also I used a local ground rod near the gate.

 

Touch wood, we've had no issues since.

 

[tjo o tjim]

Can you just get replacement interiors for those load centers here?  It looks like the enclosure works for at least 24-ways, maybe 30.

[HTC]

Back from the electrical shop. Apparently the internals to expand the load centres are not available separately.

Interesting that the guys at the shop and another sparky were not interested in the job to swap to a bigger unit.

I have a smaller square d additional load centre with me now. Will go for that option.

Thanks and I'll ask the guy about surge protection.

No more electrical plans at the moment other than what I already mentioned.

[bwpage3]

No, actually it is not a big job to change the panel.

 

You have a 100 AMP breaker box.

 

What is the supply amperage coming into your house from the pole?

 

If you only a have a 100 Amp meter on the pole, you would need to increase that as well by changing to a higher amperage meter.

 

You need to count the amps on all the circuit breakers already installed in your circuit breaker panel and see how close to the 100 AMP limit you are?

 

A swimming pool pump will pull a lot of amps, so you need to add this total amperage and any other devices you plan on adding to see what the total amperage will be.

 

The only thing about changing the breaker box is you would need to run the new wiring from the pool pump and any other new devices to the panel itself.

 

Many times the electrical conduit is hard to get new wires through or to get the new wires from outside the house, to the panel itself.

 

As far as changing the panel itself, it is pretty straight forward once you understand what your amperage requirements will be.

 

 

[sometimewoodworker]

15 minutes ago, bwpage3 said:

You have a 100 AMP breaker box.

Don't forget that it's a 3 phase supply so the minimum is 135A, and it could be 300A

[HTC]

Here is my meter.

No problem to add extra cables. I live on a hill and have access to the main power under the house.

[bwpage3]

7 hours ago, HTC said:

Here is my meter.

No problem to add extra cables. I live on a hill and have access to the main power under the house.

The photo is showing only a 15 amp meter. (15/45). If you add a pool pump, this meter will have to be increased.

[Crossy]

23 minutes ago, bwpage3 said:

The photo is showing only a 15 amp meter. (15/45). If you add a pool pump, this meter will have to be increased.

 

Not sure what size pool pump you have, a 15/45 3-phase is good for about 30kW before it even breaks sweat. It's pretty well the biggest domestic supply available outside the main towns where you may be able to get a 30/100 3-phase (66kW) which would be good for a small factory.

 

The 15A is the calibration current, the 45A is the maximum (in reality they don't even flinch at 100% overload).

 

For our OP 45A per phase is likely more than adequate. We (and most others with reasonable sized homes) have a 15/45 single phase meter, good for 10kW or so.

 

 

[HTC]

Thanks Crossy for the info on the meter. Much appreciated.

I only have a small 6m x 3m pool so the pump is also small 1hp.

Good to know I won't need anything changed out in the street.

[sometimewoodworker]

2 hours ago, bwpage3 said:

The photo is showing only a 15 amp meter. (15/45). If you add a pool pump, this meter will have to be increased.

Really you should understand the Thai supply system before making statements that are completely wrong

 

That is a meter that is calibrated to 45A per phase ( @HTC  has three phase as you can see) so the with all 3 phases within the calibration range as I said before there is 135A available and as @Crossy has said they will happy supply double the maximum calibration so 270A. Do you really think that is not enough? 

 

Of course that is the theoretical maximum and the line voltage will quite possibly be pulled way down with a load like that.

 

Now it is possible that the swimming pool is planned to become  like this

 

 

but I really think not. ???? 

[sometimewoodworker]

49 minutes ago, HTC said:

Thanks Crossy for the info on the meter. Much appreciated.

I only have a small 6m x 3m pool so the pump is also small 1hp.

Good to know I won't need anything changed out in the street.

My house has only single phase and a couple of my machines have 3hp motors and even with those and a couple of 6,500W shower heaters and a couple of AC units 3 fridges 10 fans and lots of lighting I have never come up to 45A  so you will have no problems at all. You will only need to make sure that you spread your use across all three phases (it looks as if that's already happening)

[RideJocky]

While always around, it looks to me like Sq-D is really going after the consumer market here.

I would try to contact them directly for the expansion kit.

Using Google and your existing panel number, you may be able to get the part number you need. If you give the part number to your local store they may be able order it for you.


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[carlyai]

I have a similar consumer unit (cu) in the house as the OP and 3 phase as well. I also have a smaller cu (same brand) that the incoming mains routes to first, call it cu1 (altogether 3 cu's at the moment). The bus screws are supposedly tourque wrenched tight, but I discovered one was arcing in cu1 Then on investigation it seems they all had slight burn marks around them.
So my plan was to buy another cu and swap the buses (whole innards) from the new to the old so we wouldn't have to change the cu box. We (my sparky and I)found it impossible to remove the innards and swap them over, so we ended up replacing cu1 with the new box.



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[bwpage3]

On 10/3/2019 at 8:12 AM, sometimewoodworker said:

Really you should understand the Thai supply system before making statements that are completely wrong

 

That is a meter that is calibrated to 45A per phase ( @HTC  has three phase as you can see) so the with all 3 phases within the calibration range as I said before there is 135A available and as @Crossy has said they will happy supply double the maximum calibration so 270A. Do you really think that is not enough? 

 

Of course that is the theoretical maximum and the line voltage will quite possibly be pulled way down with a load like that.

 

Now it is possible that the swimming pool is planned to become  like this

 

 

but I really think not. ???? 

Look at the gage of the feed wiring into the circuit breaker box. The box is rated for 100 AMPS maximum. That doesn't mean you can run 100 AMPS continuous. The input amperage from the meter is limited by the gage of the wires from the pole to the box, which don't appear to be 02 or 01. What is the continuous load in amps? The wire size into the box determines the amount of amps it can safely carry.

[sometimewoodworker]

3 hours ago, bwpage3 said:

Look at the gage of the feed wiring into the circuit breaker box. The box is rated for 100 AMPS maximum. That doesn't mean you can run 100 AMPS continuous. The input amperage from the meter is limited by the gage of the wires from the pole to the box, which don't appear to be 02 or 01. What is the continuous load in amps? The wire size into the box determines the amount of amps it can safely carry.

You are continuing to dig a hole for yourself. Do please admit that you do not understand what you are talking about.

 

It isn't a 15A supply meter, it maxes out at 135A for the calibrated voltage (3 X 45A = 135A)

 

Yes the box is rated at 100A but not at 220V 

it is 100A at 415V because it's a 3 phase supply so that is 3 X 100A at 220v (the combined 3 phase 415V is a little under the multiple of the individual phase voltages). This means that depending on the supply cables the only change needed to upgrade the supply would be a new 30/100 3 phase meter

 

As to the supply cable size there is no information about how far the meter is from the main CU which has red, yellow and blue phases with a white neutral.

 

It is not only the cable size but distance as well, they all look to be either 10mm² or 16mm² 

 

Oh and the 100A rating at 415V is a continuous rating, whatever gave you the idea that it wasn't.

FWIW there is an overload safety factor in everything like that so it may well be 5 X to 10 X more  and still be within the parameters for the box. Not that it matters as the supply is less than ½ the maximum of that box.

 

 

[RideJocky]

Think the voltage should be:
220 x root 3 ~ 380v

Similarly, I think the amperage should be:
45 x root 3 ~ 78v




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[carlyai]

Bit late for this, but this is my CU. So would have been easy to swap the units I think. Don't know about pulling new cables thru without draw wires already installed.

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[carlyai]

With the 3 phase SafetyCut

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[Crossy]

OK, let's get some things straight here.

 

Our OP has a 15/45 3-phase 220V supply (he is with PEA, MEA is 230V). That means his main breaker should be 45A (many are 50A or 63A on the same meter). That supply is rated at 45A, about 10kW, per-phase although the meter won't go bang or anything even at 100A (but bet it won't read low).

 

His QO3-100EZ18G / SN load-center is rated at up to 100A per phase (continuous) and 415V phase-phase (240V phase-neutral).

Square D Load Center_QO3-100EZ18G_SN.pdf

 

The main breaker is probably an Easypact EZC100B3045 (45A MCCB).

EasyPact EZC_EZC100B3045.pdf

The curves in the MCCB spec. (page 5) suggest that MCCB isn't going to think about opening below about 1.1 x rated current (>2,000 seconds at 50A), even at 100A it could take between 10s and 50s to operate.

 

It's not possible to see the size of the incoming cables, but, looking at them against the size of the breaker they are likely 16mm² which is good for 92A continuous (even if it was 10mm² it's good for 67A), a sensible contractor (ok, we are in Thailand) could have forseen an upgrade to a 100A supply and used 25mm² cable (127A).

131004_1-450!750V 70C 60227 IEC 01 (THW).pdf

 

 

Adding a 1hp (750W, 3.5A) pool pump to that installation, even if it's already near the limits (it won't be) is not going to cause anything to trip, explode, catch fire or even blink!

 

[HTC]

Many thanks for the input. This is all good information for my learning.

Here are the cables that run from overhead, through the meter and then under the house. There are 4 of them.

Also pictured is the current main breaker and the new stuff that the sparky ordered.

Are these new breakers the correct type for circuits related to water? (pump and outside lighting).

After the comments above I am confident the current system can handle the load.

[Crossy]

Looking good ????

 

Incoming breaker 50A - Check

Incoming cables 16mm² - Check

 

Your Thai sparks will probably want to run your new board off an incoming phase and the neutral. No real issue with doing that except that you lose the "single point of isolation". It's not required by the regulations anyway but is sometimes nice to have, pull one breaker and kill all the house power.

 

For safety of wet circuits I would go shopping and get a few plug-in RCBOs, so your new outdoor stuff and I'd put them on your water heaters too.

 

hhttps://www.se.com/th/en/product/QO116C10RCBO30/qovs---earth-leakage-circuit-breaker---1p-%2B-ns---c-curve---16a---30ma/?range=1095-square-d-qoe%2C-qovs%2C-qobvs&node=12367878602-residual-current-devices

 

Get the correct current rating for your circuits, usually 20A for outlets and 5A/10A for lights.

 

 

I'm not sure what that 50A single pole MCB would be useful for, you could use it to connect your new board as a sub-main from your exisiting board, but you would have to move a circuit from existing to new.

 

Take advice from your sparks on this, see what he wants to do.

 

EDIT

Alternatively, you could replace the 2-pole 50A breaker on your new board with one of these and move all your wet circuits to the new board (including your water heaters), that might be a slightly cheaper solution.

 

https://www.se.com/th/en/product/QO250C10RCBO30T/qovs---earth-leakage-circuit-breaker---2p---c---50a---30ma---10000a---ac-type/?range=1095-square-d-qoe%2C-qovs%2C-qobvs&node=12367878602-residual-current-devices

 

 

 

[maxpower]

2 hours ago, Crossy said:

Your Thai sparks will probably want to run your new board off an incoming phase and the neutral. No real issue with doing that except that you lose the "single point of isolation". It's not required by the regulations anyway but is sometimes nice to have, pull one breaker and kill all the house power.

Feed through lugs can be fitted to many Schneider TPN panels.  Worth checking to see if there is a feed through lug kit for the panel. This will allow feeding the sub panel from the bottom of the main panel bus keeping it all tidy. 

[carlyai]

Just thinking, if the OP is going to run new conduit for the new feeds to the new box, put in an extra conduit and draw wire so that the next expansion will be easier.

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[carlyai]

Having a closer look at your main box, it seems you have a spare conduit and draw wire.
Probably the best looking wiring job I've seen on this forum.

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