Is my fuse box grounded properly?

[Gulfsailor]

There have been some posts regarding grounding, and I searched online, but can't really find the answer to my question.

I live in a rental house that has most wall outlets ungrounded and would like to make a couple grounded for electric stuff like computers (which now give me nasty little shocks all the time) There are two grounded sockets in the kitchen though and I assume electric heaters are grounded as well (can't check that though since all wires are in the walls). Anyway I removed a 2-pin wall socket and there is a ground wire present. Great start!

I opened the fuse box and all looks nice and orderly installed. However I don't know if the fuse box itself is grounded properly. I have 14 positive wires, 14 negative, but 11 grounds attached, along with a thicker ground cable holding 5 or 6 cores, also attached to the ground bus. I assumed this thicker bundle was the box to ground, but then I am missing 3 grounds. Unless the three thicker positives that lead to water heaters get there ground from somewhere else. (Doesn't make sense though) also at the box all wires go straight into the wall so I can't see where the thick bundle goes.

One thing to note is that ground bus and neutral bus are not connected. Also at the meter on the pole there is no ground. Just the two main wires going into the ground towards my house.

Now I am worried that either I have a floating ground, which would put live current on all grounded metal appliances if one has a short. Or I have a ground not connected to the negative anywhere, which would prevent to breakers to break in case if a shorted ground, and running the current straight from plus into the ground continuously, risking a fire in the wires.

Any advice/tips how to check my setup??? I thought of shorting the ground at a grounded outlet to see if breaker trips or if other ground wires become live at that point, but am a lite scared of what will happen.

[Crossy]

Do post a photo of your fuse box with the lid off.

Meanwhile you can do a reasonable check of your ground by connecting a lamp (15W or so) between the live (hot) and ground connections, if it lights there is a reasonable ground.

Odd that 2-pin outlets are fitted when a ground appears to be present, it's usually the other way round (3-pin outlets, no ground).

But if those grounds are OK nothing to stop you installing 3-pin outlets solving all your shocking issues.

[Gulfsailor]

Thanks for the quick reply! Here a pic of the box. The thick cable in the middle seems the one going to rod in ground (can't find any rod though, could be under the house), but then question is why are there 3 ground wires missing, and why aren't negative and ground connected in fuse box. I now there is some kind of ground since multimeter measures 220 between positive and ground wire. But I will try a light bulb as well.

House is pretty new and but by a foreigner, so I guess they decided to already prepare all wiring for ground, even though actual sockets installed are only two-pin.

Should I just run a wire from ground to neutral bus in the fuse box???

Edited December 30, 2013 by Gulfsailor

[Crossy]

OK, standard TT system, no N-E link in this case so it's not MEN, do not install a link unless you are certain your village has MEN! But if you are going to get a Safe-T-Cut (see below) don't bother as the N-E link needs to be before this device.

Actually looks a reasonable job

I would be looking at some form of earth-leakage protection on the water heater as an absolute minimum. You can get plug-in RCBOs to fit that board at HomePro, not cheap mind

Or you could add an external whole-house RCBO (Safe-T-Cut) which may be the easier and potentially cheaper (if you are going to need more than two plug-in RCBOs) option.

[Bignose]

I may be misinterpreting this but it appears to me that you have no actual training and just a basic knowledge of electrical installation. Your handle leads me to think you may have a nautical background, it's worth noting if this is the case marine installations can be very different to domestic.

You mention receiving "nasty little shocks all the time" You also mention being worried about "a floating ground" This tells me you don't really know what your doing and as such you are a danger to yourself, and the other people in the house. Could I respectfully suggest you put your hand in your pocket and get someone in who knows what he is doing, preferably an expat contractor who has western qualifications. The various western governing bodies and safety orientated institutions have multiple listings of injuries and deaths due to either incorrect installations, or half baked modifications. I appreciate the vast majority of expats living in the LOS do so on a budget, and like myself cut corners and save money where we can, but doing your own electrical work is not one of them.

At the end of the day the choice is yours but 220V AC is not to be trifled with or bodged...

Good Luck.

[Gulfsailor]

Hi Crossy. I had to look up all the abbreviations, but I think I understand the TT setup now. So this RCBO is connected to ground, and if a large current is going through the ground wire it will trip? So in that case ground fault current doesn't need to be relieved through negative wire, eliminating need for N-E connection?

House has its own connection to power pole though, with own meter, so I am pretty sure there is no MEN setup.

In conclusion; I purchase (and have installed) 1 Safe-T-Cut (does that have to be same power rating as entire system, or just of the single strongest possible ground fault current possible?), I disregard my nonexistent N-E connection, I replace two-pin sockets with 3-pin, and I am all safe?

[Bignose]

Come to think of it does TV have an Obituary Column?

Hopefully I won't have to follow this thread there...

[Gulfsailor]

Ps. Initially I though I just ground one or two socket myself by putting rods in ground nearby (maybe with RCBO I'm the middle), but then I read that is bad idea and has fire hazards in case of lightning when more than one ground is used. I already also have a seperate ground for outside washing machine and dishwasher, so with new safe-t-cut setup I can remove that one and use new grounded socket.

[Gulfsailor]

Come to think of it does TV have an Obituary Column?

Hopefully I won't have to follow this thread there...

Hahaga. My girlfriend also doesn't like me touching this stuff. But I am wearing two pairs of rubber sandals, just to be extra safe!!!

[Gulfsailor]

I may be misinterpreting this but it appears to me that you have no actual training and just a basic knowledge of electrical installation. Your handle leads me to think you may have a nautical background, it's worth noting if this is the case marine installations can be very different to domestic.

You mention receiving "nasty little shocks all the time" You also mention being worried about "a floating ground" This tells me you don't really know what your doing and as such you are a danger to yourself, and the other people in the house. Could I respectfully suggest you put your hand in your pocket and get someone in who knows what he is doing, preferably an expat contractor who has western qualifications. The various western governing bodies and safety orientated institutions have multiple listings of injuries and deaths due to either incorrect installations, or half baked modifications. I appreciate the vast majority of expats living in the LOS do so on a budget, and like myself cut corners and save money where we can, but doing your own electrical work is not one of them.

At the end of the day the choice is yours but 220V AC is not to be trifled with or bodged...

Good Luck.

I appreciate your concerns, and you are correct that I have limited AC knowledge. (Plenty DC though designing little pet project circuit boards).

Had my share of electric shocks though in the past, both by DC capacitors and 220 AC, but still around ;-). But you are right, if it comes to more than just adding a safe t cut and changing some sockets, I will hire a professional!

[Crossy]

Your task list:-

1. Do the lightbulb test.
2. Get a Safe-T-Cut and someone to install it for you (do NOT attempt this yourself).
3. Fit 3-pin outlets.
4. Retire from further electrical work.

Your Safe-T-Cut should be rated the same or greater than your main breaker, 100A from your photo.

What meter do you have for that 100A incoming breaker? Should be a 30/100.

[Bignose]

Carry on undaunted my friend your tenacity is admirable, unfortunately your apparent disregard for those around you just doesn't quite match up...

Hopefully you get away with this with no incident of injury.

Once again good luck.

[Gulfsailor]

Your task list:-

• Do the lightbulb test.
• Get a Safe-T-Cut and someone to install it for you (do NOT attempt this yourself).
• Fit 3-pin outlets.
• Retire from further electrical work.

Your Safe-T-Cut should be rated the same or greater than your main breaker, 100A from your photo.

What meter do you have for that 100A incoming breaker? Should be a 30/100.

Will do the tasks tomorrow. (And retire after that!) Getting dark already here.

I can't find anything on the meter that says 30/100. Only resembling number is power rating 15(45)A. I checked several meters on the road and they are all 15(45), some three phase providing for big villas. Seems a bit low compared to my main breaker right? Then again all my other breakers are also ridiculously heavy. A water heater needs a 32A breaker? Per aircon 32A? I have one single group that has most downstairs plugs, light, fans, and even water pump, dishwasher and washing machine on it, and it is 20A and never tripped.

[Gulfsailor]

Carry on undaunted my friend your tenacity is admirable, unfortunately your apparent disregard for those around you just doesn't quite match up...

Hopefully you get away with this with no incident of injury.

Once again good luck.

Well the reason I am working on it is to safeguard others around me. I know plenty of places where residents just assume all is fine until someone is electrocuted in the shower. But will try to find a good electrician after the new year (not easy now as the good ones are hell busy at all resorts and hotels this time a year). Again thank you for your concern!!

[Crossy]

Oh, a 15/45 should be fused at 63A maximum, I would be getting a 63A Safe-T-Cut to protect yourself and your meter.

You evidently don't need a 100A supply.

Thai circuit grouping often strikes me as counter intuitive (ok crazy), if it's your house I would consider replacing the breakers with more sensible ratings based upon the actual connected load, if it's a renter, do the minimum to make it safe.

[Gulfsailor]

Oh, a 15/45 should be fused at 63A maximum, I would be getting a 63A Safe-T-Cut to protect yourself and your meter.

You evidently don't need a 100A supply.

Great. I was already hoping/expecting that. I will ask around for a good electrician and get the safe t cut at home pro this week. I see they are around thb 4700 for the 63A, which is a bargain for the added safety. Now just need to get a good UPS and some surge protectors, and me and my home office equipment will be super duper safe.

Thanks a lot Crossy!

[Crossy]

Sounds like a plan, by the way could you scan the Safe-T-Cut instructions and either post them here or attach to a PM to me.

And make sure your sparks reads them

[Gulfsailor]

Sounds like a plan, by the way could you scan the Safe-T-Cut instructions and either post them here or attach to a PM to me.

And make sure your sparks reads them

Will do.

[Forkinhades]

To the OP

You have a good earthing system set up, or so it seems. Without measuring your external earth, you really just do not know what you have in place in regards to safety. Let me give you an example.

External earth 10 ohms (which is acceptable on a TT system)

A 32 Amp type C MCB requires a value of no more than 0.72 ohms to OPEN in the TIME specified by ANY regs

Since you do NOT have any RCD/RCBO prortection (or whatever you like to call them) under fault conditions even with your earth system the MCB will NOT open.

You will have 23 Amps flowing to earth, so anything metal will become live, and potentially lethal.

Even with MEN connections there is NO guarantee that your values will be low enough for the MCBs to OPEN in time.

The PEA advise to install RCD protection at the front end with MEN connections, although I agree with Crossy this connection should be left to the experts.

Edited December 31, 2013 by Forkinhades

[Gulfsailor]

Ok. A quick update and question regarding above proposed steps.

A 60watt light works between live and earth, so I guess my grounding is at least decent

I checked all the poles on the road and none are grounded, so clearly not MEN.

And I found a Thai sparky with an actual degree who will come have a look tomorrow. However when I mentioned an RCD, he said it would trip all the time. We are on Samui and power brownouts and blackouts are a very regular occurrence. So no one is using these 'fancy mainland devices' here....I thought the RCD would just measure the demand side, not supply side, but Googling this issue, apparently it is common that RCD's trip when there is a blackout or significant brownout. Any input on this matter will be highly appreciated!

[Crossy]

With a TT system an RCD is an absolute requirement for safety, the ground you have is simply not going to be good enough to open an MCB in the event of a L-E short.

Up2U of course, safety or constant power (if it trips you turn it back on).

[Gulfsailor]

Relating to the above; if an RCD is likely to trip at a brownout, then why doesn't the ELCB in the electric shower heater have the same problem? Sometimes the power drops to 180V, all lights go dim, and shower barely warms the water at all anymore, but the ELCB doesn't trip.

[Gulfsailor]

With a TT system an RCD is an absolute requirement for safety, the ground you have is simply not going to be good enough to open an MCB in the event of a L-E short.

Up2U of course, safety or constant power (if it trips you turn it back on).

I agree with you on safety first. But with dozens of little brownouts and blackouts a day in the rainy season, that will be a severe nuisance. Anyway to prevent it with another device?

[Crossy]

With the modern devices RCDs tripping on brownouts is much less common than it used to be, we've never had an RCD open on a brownout (surge, yes).

[Gulfsailor]

With the modern devices RCDs tripping on brownouts is much less common than it used to be, we've never had an RCD open on a brownout (surge, yes).

Ok thanks. I will tell the sparky to install the Safe-T-Cut then, and hope it doesn't trip too often.

I looked at the ones to replace the standard group breakers in my panel, but could only see the ones that have the width of two standard breakers. Does that mean I just stick two groups into that one new breaker? And are there 3 or 4 group versions available that fit my panel? Online in Europe plenty, but at Homepro they had very little assortment (for instance only one safetcut model)

[Crossy]

I would get a Safe-T-Cut unit and put in front of the whole installation, you can also set it to 'direct' to stop it tripping on really bad evenings (not recommended mind).

RCBO devices to replace your incomer are available for that board but they are *&^% expensive and will need to be ordered

You can get single width units for that board, but they only protect the once circuit, so you'll need several, again $$$

[wolf5370]

Ok. A quick update and question regarding above proposed steps.

A 60watt light works between live and earth, so I guess my grounding is at least decent

I checked all the poles on the road and none are grounded, so clearly not MEN.

And I found a Thai sparky with an actual degree who will come have a look tomorrow. However when I mentioned an RCD, he said it would trip all the time. We are on Samui and power brownouts and blackouts are a very regular occurrence. So no one is using these 'fancy mainland devices' here....I thought the RCD would just measure the demand side, not supply side, but Googling this issue, apparently it is common that RCD's trip when there is a blackout or significant brownout. Any input on this matter will be highly appreciated!

I live out a bit from town (CM), and get regular power cuts - and my UPS catches trips (it logs anything from switch overs up) hundreds of times a day. First thing I did was put in a T-Cut (yes got a sparky to do it - In the UK I once completely replaced the house wiring - and also did the lighting in my restaurant, but here I use a sparky for anything before the consumer unit - 50+A would sting like a b!tch) - trips occasionally on the lowest setting, but minor adjustment and it only trips when its meant to (like a month or two ago when the shower ECB flipped and resetting tripped the T-Cut). It is still well in the green (T-Cut settings side) - we have a big load on all the time with multiple computers and fridges never off, electric baking oven, air con (although its never on), 5KW shower etc. Shower trip was fixed btw.

At a house I used to rent I de-installed a shower heater (to replace), and switched off the breaker for it. Tested with metre etc - but still got blown across the room (off the top of a metal ladder!) due to poor wiring - never trust the breakers, things can be wired backwards here and even crossed, someone flips on a light somewhere else and suddenly its hot again. Hence I put in T-Cuts now when I move (I spent 10k on mine - fitted - got an 85A). Now when I do any work, like replacing outlets or putting in spurs, I turn it off at the T-Cut (it has a switch for it without triggering), so all power through the house is off - just don't trust it any more.

[Gulfsailor]

I would get a Safe-T-Cut unit and put in front of the whole installation, you can also set it to 'direct' to stop it tripping on really bad evenings (not recommended mind).

RCBO devices to replace your incomer are available for that board but they are *&^% expensive and will need to be ordered

You can get single width units for that board, but they only protect the once circuit, so you'll need several, again $$$

I was thinking to put a couple of the more risky groups (like bathroom and kitchen) on individual RCBO's, with the main safe t cut covering all. Am I right that in such case the RCBO trips and leaves the RCD untripped. It's nice to not have the entire house dark or office offline when there is a single problem somewhere.

As per your recommendation to set the safe t cut direct at bad times, it then at least has the important wet rooms still protected via those RCBO's. Where can I order RCBO's online???

[bankruatsteve]

Take a photo of your box would help. A good alternative is to replace the main breaker with RCBO.

Oops, somehow missed the last two posts so not sure what I replied. (?) Anyway... RCBO is same as front end RCD except it also has overcurrent protection. Whatever makes sense for the cost: either will do it.

Edited January 9, 2014 by bankruatsteve

[Forkinhades]

I would get a Safe-T-Cut unit and put in front of the whole installation, you can also set it to 'direct' to stop it tripping on really bad evenings (not recommended mind).

RCBO devices to replace your incomer are available for that board but they are *&^% expensive and will need to be ordered

You can get single width units for that board, but they only protect the once circuit, so you'll need several, again $$$

I was thinking to put a couple of the more risky groups (like bathroom and kitchen) on individual RCBO's, with the main safe t cut covering all. Am I right that in such case the RCBO trips and leaves the RCD untripped. It's nice to not have the entire house dark or office offline when there is a single problem somewhere.

As per your recommendation to set the safe t cut direct at bad times, it then at least has the important wet rooms still protected via those RCBO's. Where can I order RCBO's online???

To get discrimination you have to get a front end Safe-T-Cut rated at 100mA

RSonline thailand

Note that at RS they will not be called Safe-T-Cut but RCD.

But they do RCBOs as well

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