Using Rcd'S In Thailand - Electrical Question

[AllanB]

I don't know whether there are any electricians out there, but does anyone know why an RCD consumer unit would not work here. They don't use them here, but they make swimming pools much safer.

I have one wired in and it keeps tripping out, have done a quick bell out and can't find a fault.

Help appreciated.............

[Crossy]

They do work just fine, indeed are an absolute requirement on new installations.

If yours is tripping then you have a fault.

What tests did you perform with your 'quick bell'? Insulation N-E and L-E?

I would avoid having ANY mains powered equipment near a pool, underwater lights particularly as these have been the cause of many deaths over the years, often in hotel pools

[fdimike]

Alam

I have to agree with Crossy. I have two of these devices installed in my house - one for the main house and the other for all the pool equipment. We call these GFCI (Ground Fault Circuit Interupter)in the US. The ones I have installed at my house in Udon Thani also state GFCI and are made by Safe-T-Cut.

I would disconnect (not switch off) all appliances, lights (inc outdoor lights & ceiling ) etc and try resetting the device. If it still trips the problem is somewhere in the wiring, or outlets. If it doesn't trip then you probably have a fault in a light or appliance etc.You should also check all your electrical outlets to see if they are wired correctly (correct polarity).

BTW: I'm not an electrician just a homeowner who grew up with a Dad who was a building contractor and made sure I learned everything I could about what goes into a building and how it's supposed to work.

Hope this helps.

[AllanB]

Yes, the wiring is okay, if I bypass the RCD everything works, lights and pump.

[Crossy]

Yes, the wiring is okay, if I bypass the RCD everything works, lights and pump.

Have you done an insulation test? What are the results?

Just because things work does not mean they are safe! If you suspect the RCD is faulty, replace it, but do not bypass it particularly in a pool environment.

You need to determine which circuit is causing the beast to trip. Easy enough to decide if it's the lights or the pump, disconnect each in turn and see which causes the trip.

Are those mains voltage lights in the pool? If so do yourself a favour and replace them with low voltage lighting.

[Crossy]

Is this a new installation?

Please post a clear photo of the wiring in the offending consumer unit.

An RCD that trips as soon as a load is applied is often a wiring error. And yes, it may still work if the RCD is bypassed but it won't be safe.

[AllanB]

I wasn't aware that RCD's were used in Thailand, I haven't seen any, none of the electrical suppliers in KK have them, my house is relatively new and well built but doesn't have one. So if they exist here, maybe I could find a sparks to check it, all the ones I know, know less than me.

The pool has not yet been filled, so any bypassing is only temporary, I know about the dangers of water, that is why I fitted an RCD CU, which I bought in the UK, my friend has a pool by JD Pools and his doesn't have one as far as I know. His 6m baht house doesn't, I am sure.

Now the fault itself, the consumer unit has two outputs:-

1. I set the RCD to on, the 6amp isolator off, the 16amp isolator on and when I switch on the pump at the timeswitch, the RCD trips.

2. With the RCD back on, the 16amp isolator off, the 6amp isolator on, when I turn the pool lights on at the switch, the RCD trips.

3. Sometimes the RCD trips when the pump is on the "off" position at the time switch.

The chances of the same fault on both circuits is remote.

I do have a second consumer unit, if this one is faulty, but thought I would check this one first.

The lights are not in the pool, they are in the roof which is all steel.

I installed a 1 metre earth rod by the pool panel (though I understand now it should be 1.5m) and I read about a MEN link, but don't know what that is.

If this were in the UK I wouldn't be doing this, but TIT.

[Crossy]

I'll re-iterate my request for photos of the wiring in the CU and test results. We all make mistakes and sometimes it takes a second pair of eyes to see them.

What you describe is a classic example of a N-E short although other faults could cause similar effects.

If you have another unit it will do no harm to swap like for like, it's always possible the RCD is faulty.

When talking to your sparks use the name 'Safe-T-Cut', these are a local brand and seem to have become synonymous with RCD.

Your local HomePro, HomeWorks or Boonthavoorn assuming they've made it to KK should have RCDs

[AllanB]

Is a "Safe-T-Cut" an RCD, I thought it was a simple circuit breaker? In that case the house has this within the consumer unit, so I don't need another for the pool and could bypass this and use only the MCB's in the CU.

What happens if (in this case) there are two RCD's within the same circuit, could that cause the problem?

Also the "Safe T Cut" in my house consumer unit has no test button, so how do I know it is working?

Now, I just looked on the "Safe T Cut" website and it is a trade name for their products, not all of which are RCD's, mine looks similar to http://www.safe-t-cut.com/eng/index.php?name=product&file=readproduct&id=13 and nowhere in the description does it mention RCD protection.

[Crossy]

Safe-T-Cut do indeed make things other than RCDs. As I said, the name has become synonymous with RCD as at one time that's all they made. So using the phrase 'Safe T Cut' is useful in talking to a local sparks to get the idea over that you want an RCD, it's not a one-size-fits-all phrase. A bit like using the word 'hoover' in the UK, everyone associates Hoover with vacuum cleaners despite the fact that they make a whole range of domestic white goods.

If it has no 'Test' button it's not an RCD so you won't be chaining multiple RCDs.

If you do have multiple RCDs there is no safety issue, just you won't be able to determine which one will trip first in the event of a fault.

Photos and test results would still be helpful in fixing your pool issue. If you don't have an insulation tester, use a regular multimeter (not perfect but better than nothing), measure on high Ohms between L-N, N-E and L-E. Help me and others to help you

Did you swap the RCD with your spare unit yet? Result?

[AllanB]

Safe-T-Cut do indeed make things other than RCDs. As I said, the name has become synonymous with RCD as at one time that's all they made. So using the phrase 'Safe T Cut' is useful in talking to a local sparks to get the idea over that you want an RCD, it's not a one-size-fits-all phrase. A bit like using the word 'hoover' in the UK, everyone associates Hoover with vacuum cleaners despite the fact that they make a whole range of domestic white goods.

If it has no 'Test' button it's not an RCD so you won't be chaining multiple RCDs.

If you do have multiple RCDs there is no safety issue, just you won't be able to determine which one will trip first in the event of a fault.

Photos and test results would still be helpful in fixing your pool issue. If you don't have an insulation tester, use a regular multimeter (not perfect but better than nothing), measure on high Ohms between L-N, N-E and L-E. Help me and others to help you

Did you swap the RCD with your spare unit yet? Result?

Okay, sorry for the delay been doing other urgent things...

I only have an analogue meter, so roughly L-N = 5ohms, N-E = 2ohms, L-E 2ohms

Attached is a picture of the panel.

Any help appreciated, I was told a digital meter would determine which is the house live, as I have used an existing outside feed, so may get one, any suggestions?

[AllanB]

Safe-T-Cut do indeed make things other than RCDs. As I said, the name has become synonymous with RCD as at one time that's all they made. So using the phrase 'Safe T Cut' is useful in talking to a local sparks to get the idea over that you want an RCD, it's not a one-size-fits-all phrase. A bit like using the word 'hoover' in the UK, everyone associates Hoover with vacuum cleaners despite the fact that they make a whole range of domestic white goods.

If it has no 'Test' button it's not an RCD so you won't be chaining multiple RCDs.

If you do have multiple RCDs there is no safety issue, just you won't be able to determine which one will trip first in the event of a fault.

Photos and test results would still be helpful in fixing your pool issue. If you don't have an insulation tester, use a regular multimeter (not perfect but better than nothing), measure on high Ohms between L-N, N-E and L-E. Help me and others to help you

Did you swap the RCD with your spare unit yet? Result?

File didn't load will try again, haven't tried 2nd RCD, don't want to damage both, if it is my wiring fault.

Okay, sorry for the delay been doing other urgent things...

I only have an analogue meter, so roughly L-N = 5ohms, N-E = 2ohms, L-E 2ohms

Attached is a picture of the panel.

Any help appreciated, I was told a digital meter would determine which is the house live, as I have used an existing outside feed, so may get one, any suggestions?

[AllanB]

Okay I have replaced the RCD section of the consumer unit, no change, RCD trips as before.

I have isolated the pump side completely, lights trip RCD

i have isloated the lights side completely, pump trips RCD, even before the pump is started at the timeswitch.

I have bypassed the timeswitch, RCD trips when I start pump.

Everthing works okay if I bypass the RCD.

I disconnected the earths, no change to RCD action.

With nothing upstream of the CU making any difference, this sounds like multiple faults, or am I too close to see the obvious?

[AllanB]

It probably makes no difference, but I exchanged both MCBs and put a new neutral cable in the CU, so everying in the CU is the new.

I am lost.......

[Forkinhades]

It probably makes no difference, but I exchanged both MCBs and put a new neutral cable in the CU, so everying in the CU is the new.

I am lost.......

As Crossy stated, it sounds very much like an neutral/earth fault, ie the cables have been crossed, in which case it will never work. You will need to disconnect all the neutrals from the CU, and reconnect them one at a time, until the RCD trips again, once you have found that further investigation is required to see where the neutral and earth have been crossed.

These devices really DO NEED to be checked with the right equipment by a professional.

[Forkinhades]

At first glance of your pic, I thought hey that nice and neat, then I noticed the connector inside the RCD/MCB enclosure. Should never have this on a new install, this on its own highlights how poor the workmanship is.

[AllanB]

If I could find a professional I wouldn't be on this forum and non-constructive criticism isn't helpful. But to answer your point, I cannot find a junction box here, so will correct this when one arrives from the UK..

I mentioned that I already isolated both L and N on each circuit, to no avail.

If anyone knows of a qualified electrician (English speaking) in Khon Kaen, please let me know.

In the meantime could anyone advise as to whether the 1 metre earthbar is sufficient, since the house only has no earth at all. So Thai electrician's workmanship a dam_n sight worse than mine then?

[Crossy]

I count three black wires all of which go to the neutral bar, so it looks like your incoming neutral is going to the neutral bar, it should go to the incoming neutral terminal of the RCD.

Incoming Live and incoming Neutral must ONLY go to the RCD input terminals if the device is to operate correctly.

If it is wired like that the RCD will trip any time the load goes over about 15mA.

A 1 metre ground stake is likely to be marginal, unless you can actually test it I'd either add another (at least 2m away) or add an extension to the existing one.

EDIT. You also seem to have a lot of red wires going in (five ?) but only three in the top of the MCB and RCDs.

A simple check for a CU is that there should be an equal number of lives and neutrals going out.

Do you have your intended wiring diagram that you can post?

[Forkinhades]

non-constructive criticism isn't helpful

Its YOUR life pal

[Forkinhades]

1 metre earthbar is sufficient

Again this needs to be tested with the proper equipment, but I would say that it is ok , because the RCD is WORKING, or so it seems.

Could you up a picture of your main fusebox.

We are trying to help

[Forkinhades]

So Thai electrician's workmanship a dam_n sight worse than mine then?

should have realised because thais dont generally use connector blocks, normally screwcaps

[AllanB]

Solved it, a simple wiring error, bought the incomming neutral to the bus bar instead of the RCD, thanks to a guy back in the UK on a DIY site.

[Crossy]

Solved it, a simple wiring error, bought the incomming neutral to the bus bar instead of the RCD, thanks to a guy back in the UK on a DIY site.

As per Post #18 good that you solved it.

I'm still confused by the number of red wires entering the CU, does that choc-bloc have anything to do with them?

[Forkinhades]

Solved it, a simple wiring error, bought the incomming neutral to the bus bar instead of the RCD, thanks to a guy back in the UK on a DIY site.

Good Luck

and I hope your earth is sufficient enough to provide you with protection, and trip your RCD in the time specified under fault conditions

[AllanB]

That is the light swtch connection and no it shouldn't be there, when I get a terminal box it will go in there, but safe for now away from fingers.

I will fit a new earth rod, 1.5 metres is supposed to be enough, may go for 2m, pushed the 1 metre one in with my foot. I will also instal one for the house, the shower earth is wired into the house CU, but not connecetd to anything. TIT.

If I were thinking clearly I would have realised the RCD it measuring L and N, can't do that if I don't connect N to it.

We all make mistakes as the Darlek said as it climbed down off the dustbin.

[Crossy]

That is the light swtch connection and no it shouldn't be there, when I get a terminal box it will go in there, but safe for now away from fingers.

I will fit a new earth rod, 1.5 metres is supposed to be enough, may go for 2m, pushed the 1 metre one in with my foot. I will also instal one for the house, the shower earth is wired into the house CU, but not connecetd to anything. TIT.

Personally I would leave the choc-bloc as it it is, it's safe and away from potential disturbance. You may wish to add a label to the cores.

Without proper testing it's impossible to say whether an earth is adequate, adding another rod cannot hurt.

Is your shower protected by an RCD? If not install one when you add the ground rod.

[Forkinhades]

We all make mistakes as the Darlek said as it climbed down off the dustbin

lol

Seriously you need to measure your earth, might save you having to buy more rods if the reading is 'low' enough, and indeed will protect you against death under fault conditions.