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Drawing Too Much Electricty / Consumer Unit / Plastic Consumer Unit Box

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In the UK, under what ever directive (I think 17th) it is compulsaory to use a metal consumer unit box.

 

I took a few Schneider Consumer Units to Thailand from the UK.

They are plastic as per picture with the standrd 2 RCDs and MCBs

I also took some 10 Amp and 20 Amp MCBs as seem to be commonly used in Thailand.

 

Is there any rules in Thailand regarding using a plastic consumer unit?

I actually feel that they are safer than a steel one.

 

P1000152.thumb.JPG.f85532afc7e66e5f649d4d7ba4b8e56f.JPG

 

 

I intend to use two of these consumer units.

One for upstairs and one for downstairs (2 floor house)

 

I shall supply both of them from a single 63 Amp MCB worrying about overloading the Mains Supply Cable.

 

I am running the following off the two consumer units:

 

DOWNSTAIRS:

Shower 4500 watt

Expresso Coffee Machine  4200 watt

Water heater  2000 watt

UK electric kettle 3000 watt

Air conditioning Unit

 

UPSTAIRS

2 No Showers 4500 watt

2 Air Conditioning Units

 

Am I overloading my supply?

This is the reason for putting a 63 Amp MCB on the Mains Supply.

 

 

 

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34 minutes ago, Cashboy said:

Is there any rules in Thailand regarding using a plastic consumer unit?

I actually feel that they are safer than a steel one.

No problem, all my CU’s are plastic. 76F6FC56-3FD1-4F80-9C58-3B68357FF706.jpeg.ebd0b4b00de2ed68298a876378559bbc.jpeg
 

and you are not stressing your supply.

Edited by sometimewoodworker

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3 hours ago, daveAustin said:

Plastic is a fire hazard.

Not the plastic used in those as it’s self extinguishing. But your point is?

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My CUs are all plastic too. The UK regs actually specify "non combustible" which everyone reads as "metal".

 

With a 63A incoming MCB and a 15/45 meter you won't be overstressing the supply.

 

Do you have a permanent meter yet? If not the PEA inspector may not like the 63A incomer, just replace it with a 50A unit until he's gone 🙂

 

Also, ensure you wire to Thai requirements, the UK regs are very good but things like ring-finals are a no-no, AS3000 (Aussie regs) is actually a better fit for here.

 

A handy-dandy PEA document Groundwire Mk2 book-Manual.pdf

 

And the important bit with translations, note the routing of the incoming neutral via the ground bar, this is the Thai implementation of MEN (similar to PME).

 

Groundwire Mk2 book-Manual-1 diagram.jpg

 

 

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12 hours ago, Cashboy said:

metal consumer unit box.

seen a  few  videos  saying this is  nonsense and useless from UK electricians

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On 12/8/2019 at 10:19 PM, Crossy said:

 

Also, ensure you wire to Thai requirements, the UK regs are very good but things like ring-finals are a no-no, AS3000 (Aussie regs) is actually a better fit for here.

 

What do you mean by "ring-finals are a no-no"?

 

Do you mean running a 2.5 mm2 ring from the consumer unit with a 30 Amp MCB is not legal in Thailand

 

I have about 80 (4" x 4") metal boxes in the house for power, with each box taking 4 electric sockets in.

So if I was running it on a 20 Amp MCB, how many of these metal boxes (with 4 electric sockets in) can I connect to one 20 Amp MCB?

 

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On 12/8/2019 at 10:19 PM, Crossy said:

 

 

Groundwire Mk2 book-Manual-1 diagram.jpg

 

 

That does not make sense to me !

In the UK after the meter, I have the live and neutral going to the consumer unit and the earth connected to the armour plating of the incoming mains cable.

The neutral mains is NOT connected to the earth in my UK house as far as I can see.

 

This was my plan:

 

Electric.png.de3719e8476cd19029833739e4b4e209.png

 

 

 

 

 

 

 

 

 

 

 

 

 

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15 minutes ago, Cashboy said:

What do you mean by "ring-finals are a no-no"?

 

Do you mean running a 2.5 mm2 ring from the consumer unit with a 30 Amp MCB is not legal in Thailand

 

I have about 80 (4" x 4") metal boxes in the house for power, with each box taking 4 electric sockets in.

So if I was running it on a 20 Amp MCB, how many of these metal boxes (with 4 electric sockets in) can I connect to one 20 Amp MCB?

 

Ring-finals are mostly an English thing.  If not expected, they can be hazardess to the unknowing spark.

With 80 boxes, you would want as many circuits as you can support.  It's not the count, but what you anticipate plugging in that will determine.

 

Edited by bankruatsteve

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1 hour ago, Cashboy said:

What do you mean by "ring-finals are a no-no"?

 

Do you mean running a 2.5 mm2 ring from the consumer unit with a 30 Amp MCB is not legal in Thailand

 

I have about 80 (4" x 4") metal boxes in the house for power, with each box taking 4 electric sockets in.

So if I was running it on a 20 Amp MCB, how many of these metal boxes (with 4 electric sockets in) can I connect to one 20 Amp MCB?

 

Ring finals are even deprecated in the UK. It’s quite possible that they may even be banned for new builds in the not too distant future 

 

They have a 32Amp requirement. Split the ring and each radial gets a 20Amp to 25Amp breaker, so you have immediately gained an extra 8Amp to 18Amps available.

 

The numbers of sockets you can put on radials is basically unlimited (even in the UK). However the load should not exceed 25Amps for an extended period, so the number of sockets is most often limited by that requirement.

 

As to why ring finals are a bad (arguably very bad to stupid idea) 

1) find any electrician here who can understand them.

2) find any electrician here who can install them

3) find any electrician here who can trouble shoot them when the installation goes wrong

4) find any electrician here who can check to see if they have been installed correctly. (Sometimes even a challenge in the UK)

5) and most importantly ring finals have different failure modes that are very capable of leaving appliances apparently off but in fact they are at 220V as the ring has failed in an exciting (for someone watching who has a life insurance policy on you) 😉 way. 

 

 


 

Edited by sometimewoodworker
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1 hour ago, Cashboy said:

Do you mean running a 2.5 mm2 ring from the consumer unit with a 30 Amp MCB is not legal in Thailand

 

Correct! Thai plugs are un-fused and rated at 16A. There's no protection for the appliance flex other than the MCB (your 0.5mm2 fan flex is going to be glowing before a 30A breaker operates). Run 2.5mm2 radials on 20A breakers like everyone else, just run more of them.

 

1 hour ago, Cashboy said:

The neutral mains is NOT connected to the earth in my UK house as far as I can see.

 

But you can't see in your service head. Having TN-S in the UK is becoming increasingly rare, a massive number of supplies are now TNC-S (with the N-E split in the service head) mainly due to the deterioration of the cable armouring which was providing the earth path.

 

Your plan actually looks pretty OK, close to what we have, just make your N-E connection on the incoming side of your changeover switch and you'll be good to go. Make it look like the Thai authorities want and they will be happy.

 

I would put the 63A MCB on the supply side of the changeover otherwise there's no protection for the switch (no DNO fuses here).

 

EDIT It's also worth noting that the inspector is going to want to see some form of earth leakage protection. If you're not going for multiple RCBOs then stick an RCD on the load side of the 63A breaker.

 

EDIT 2 Looking back I see those CUs have dual RCDs - Perfect!

You may want to adjust the RCD positioning to enable an un-protected circuit for your freezer 🙂

 

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Also:-

 

Run 6mm2 for your showers and water heater, you won't need it for the 4.5kW unit but after a few chilly nights you may want to upgrade (we have an 8kW unit in the master bathroom).

 

Run individual radials for your aircons, 2.5mm2 and 20A breakers will be fine unless they are huge units.

 

 

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52 minutes ago, Crossy said:

 

I would put the 63A MCB on the supply side of the changeover otherwise there's no protection for the switch (no DNO fuses here).

 

The reason that I was putting the 63A MCB after the changeover switch (125 Amp) was to protect the amount of ampage drawn out from either the Mains or the Generator.

 

When I look at that government drawing connecting the Neutral to the Earth, I cannot see the reason for having an earth rod as it appears the earth is travelling to the government neutral anyway.

 

 

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5 minutes ago, Cashboy said:

When I look at that government drawing connecting the Neutral to the Earth, I cannot see the reason for having an earth rod as it appears the earth is travelling to the government neutral anyway.

MEN: Multiple Earthed Neutral

The CU is a critical point.

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9 minutes ago, Cashboy said:

The reason that I was putting the 63A MCB after the changeover switch (125 Amp) was to protect the amount of ampage drawn out from either the Mains or the Generator.

 

When I look at that government drawing connecting the Neutral to the Earth, I cannot see the reason for having an earth rod as it appears the earth is travelling to the government neutral anyway.

 

Is your genset really going to be able to open a 63A MCB? I would protect it separately with a suitable MCB.

 

Thailand uses the MEN (Multiple Earthed Neutral) system (like Aus and NZ), the neutral is grounded at multiple points, at the installation and at every 3rd pole or so. This is to mitigate the hazard from an open neutral in a TNC-S system.

 

If you really don't like it then once the inspector has gone convert to TT.

 

 

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