How to earth a new domestic electrical supply?

[Encid]

Recently my wife and I decided to develop part of her family farm and plan to build a new house on it in the near future.

We contacted a builder and he installed some poles and electrical cable overland from the nearest PEA pole to our building site.

We then contacted the PEA who installed our meter and connected our wiring to the grid.

It is a 30A 220V single phase 2 wire supply.

But our supply is not earthed or grounded, neither at the meter nor at the junction box at the building site.

What can we do to rectify this?

 

 

 

 

 

[Muhendis]

Incoming neutral should be grounded at every fourth or fifth post so neutral is your ground. at the switchboard a new ground can be added by driving a ground rod into the soil. it needs to be at least 2.4M and adjacent to the switchboard post. This is your earth and can be connected to the neutral output of the isolator switch. The neutral is now also your ground and can be connected to any metallic bits of the pump etc. I prefer to run a separate earth conductor to pumps etc. and terminate at the earth bus-bar in the CU.

[Crossy]

This is how you must do it to pass a PEA/MEA inspection (my translations). Note the routing of the incoming neutral via the ground bar.

 

Originally from this PEA document Groundwire Mk2 book-Manual.pdf

 

[Crossy]

For your construction supply I would simply run a wire from the ground pins of the outlet to a rod next to the pole, the word "safe" never applies on a Thai construction site. You can bet the contractor won't have any kit with 3-pin plugs anyway.

 

When you do your final installation I'd be tempted to retain that box and breaker as a site-isolator.

[Encid]

On 5/19/2022 at 4:31 PM, Crossy said:

For your construction supply I would simply run a wire from the ground pins of the outlet to a rod next to the pole

Do you mean the outlet sockets or the main breaker switch? See the photo above.

 

On 5/19/2022 at 4:31 PM, Crossy said:

When you do your final installation I'd be tempted to retain that box and breaker as a site-isolator.

That is a really good idea thanks!

 

Our plan is to run all our feeder wiring underground in HDPE conduit, initially to our first build (a 1 bedroom 1 bathroom guesthouse) where it is intended to install a proper MCB/RCD complete with grounding electrode, and the same to our secondary and later build (the main house).

Both constructs will be at different locations on the site so different feed cables/conduits will be run from that box.

Having a whole of site isolator is a great idea.

 

Do you think it would be wise to change the active wiring to black cable and leave the neutral as white?

Obviously earth or grounding cables should be green.

 

Where can I buy a ground rod/electrode?

Is this a job I can do myself?

 

As part of my wife's family are self-isolating themselves on the farm now (due to rampant COVID outbreaks in the village) they are currently running an extension lead from that box to their shelter about 30m away.

They use the power for a fan, a radio, and to power a new 250W water pump.

None of that is currently earthed.

I want to make sure that they are safe. 

[Crossy]

15 minutes ago, Encid said:

Do you mean the outlet sockets or the main breaker switch? See the photo above.

 

The third pin of the outlets that's not currently connected.

[Crossy]

Get a rod at any DIY place.

 

Black is the favourite colour for cable of any sex, tape or (preferably) heatshrink of the relevant shade is your friend.

 

The link from the isolator to the outlet really matters not, it's temporary and will be gone once the house is built.

[Muhendis]

13 minutes ago, Crossy said:

it's temporary and will be gone once the house is built.

Oh yeah?

If the sockets do get left in the isolator box, put an MCB in there with them. That will give a bit of safety for all the gardening things etc. that will surely get to use that handily located power point. Plus an RCD would be even better.

[Encid]

22 hours ago, Crossy said:

Get a rod at any DIY place.

Is it OK to just hammer them into the ground?

What size cable should I use to connect to it from the ground pins of the outlets?

 

[Crossy]

4 minutes ago, Encid said:

Is it OK to just hammer them into the ground?

What size cable should I use to connect to it from the ground pins of the outlets?

 

For a temporary job a bit of the same stuff that goes breaker => outlets, add some green tape if you like.

 

If the builders actually have a lead with a plug on the end you'll be lucky, I bet they just wire straight into the breaker, hopefully on the switched side

[Crossy]

This was our temporary supply. The Chang switch (in the custom weatherproof housing) did actually have fuses but they popped when the welder was fired up.

 

The replacement 2.5mm² "fuse wire" was never troubled during the rest of the build ???? 

 

[NanLaew]

26 minutes ago, Crossy said:

 

For a temporary job a bit of the same stuff that goes breaker => outlets, add some green tape if you like.

 

If the builders actually have a lead with a plug on the end you'll be lucky, I bet they just wire straight into the breaker, hopefully on the switched side

If the 'temporary' breaker box becomes part of something bigger in the future, I would go ahead and use 4 or 6 mm wire for the ground rod now, just in case it all gets forgotten about.

[Crossy]

2 minutes ago, NanLaew said:

If the 'temporary' breaker box becomes part of something bigger in the future, I would go ahead and use 4 or 6 mm wire for the ground rod now, just in case it all gets forgotten about.

 

I'm assuming that the house will have a properly configured consumer unit (per my diagram) and that breaker will actually become a site-isolator.

 

But why not ???? 

 

As noted earlier adding a 500 Baht RCBO to the outlets would actually make them safe.

 

Then, enter the Thai builders!

[surreybloke]

Hello I am newish to this forum.    My lady friends farm needs a little updating.   Ideally I would like to improve the standards of  the domestic installation.    The previous posts are excellent .     

Having said that do  qualified sparkies exist in Isaan  who are capable of testing the resistance and other tests.   

Looking at the photo would it have been to much to ask for a cover over the breaker to stop someone touching exposed conductors

[Crossy]

5 hours ago, surreybloke said:

Looking at the photo would it have been to much to ask for a cover over the breaker to stop someone touching exposed conductors

 

Welcome to Thailand and Thai electrical installations ???? 

 

Why not start a separate thread with some photos of what's there already and we can point you in the most economical direction for your upgrade?

[sometimewoodworker]

On 6/12/2022 at 11:27 PM, surreybloke said:

Having said that do  qualified sparkies exist in Isaan  who are capable of testing the resistance and other tests.   

Looking at the photo would it have been to much to ask for a cover over the breaker to stop someone touching exposed conductors

Yes qualified sparkies exist, though if you keep your location secret you’re unlikely to get referrals. They are few and far between, I know one, my location is on every post.

 

If you actually look at the photo you will see that the fuse is being changed so the cover that does exist for those switches cannot be on it at the time of the picture.
 

It’s certainly possible that the cover is missing but much more likely (given the creative water protection) it’s just out of the shot

[bluejets]

13 hours ago, sometimewoodworker said:

If you actually look at the photo you will see that the fuse is being changed so the cover that does exist for those switches cannot be on it at the time of the picture.

Fuse...??? ..........looks like a bit of solid core copper wire to me..........????

[Crossy]

34 minutes ago, bluejets said:

Fuse...??? ..........looks like a bit of solid core copper wire to me..........????

 

Yup, it was 2.5mm2 copper wire.

 

Never blew again during construction ????  

[sometimewoodworker]

59 minutes ago, bluejets said:

Fuse...??? ..........looks like a bit of solid core copper wire to me..........????

What is a fuse?  Answer, it’s a bit of solid core wire. 
 

Now of course good ones are in sand inside a ceramic tube, and the wire is designed to melt long before the conductors it is protecting get too hot. But despite all that a piece of 2.5mm copper wire is a fuse, it just won’t provide any protection for 2.5mm cable. ???? 

@Crossy could probably have used 1mm wire for a degree of protection ???? but TIT and bigger is better isn’t it? 55555

 

[bankruatsteve]

Other than fuses, I don't think I have ever seen a wire melt from over-current (that is not a short).  Not saying that doesn't happen, just not in my experience.

[Sophon]

On 6/12/2022 at 11:27 PM, surreybloke said:

Looking at the photo would it have been to much to ask for a cover over the breaker to stop someone touching exposed conductors

This is what the incoming breaker looked like during our build:

 

At least they never replaced the fuses with solid wire.

 

Things haven't got much better since then. This is what our meter have looked like for the last five years, during which time we have repeatedly asked the PEA to come and put on a cover. I have even offered to put on the cover myself, if they would just give me one.

 

The meter is on a public road and in reach of kids and buffaloes (which graze on the empty land next door). 

[carlyai]

We had a knife switch like that on one of the buildings in the compound. BIL's eldest son was washing his car near the switch and put his hand in the switch. Goodbye. 

[Crossy]

4 hours ago, bankruatsteve said:

Other than fuses, I don't think I have ever seen a wire melt from over-current (that is not a short).  Not saying that doesn't happen, just not in my experience.

 

You might try brushing with one of the solar battery packs, ours will easily melt 6mm²!

Ask me how I know

Of course that was a short.

[sometimewoodworker]

5 hours ago, bankruatsteve said:

Other than fuses, I don't think I have ever seen a wire melt from over-current (that is not a short).  Not saying that doesn't happen, just not in my experience.

My mother would have been able to tell you all about a situation just a little short of that.

 

She was an extremely intelligent lady but didn’t know the problems caused by running a 2kW ~ 3kW heater using an extension cable that was still mostly on its reel. It was a high quality extension and luckily she was near enough that the smell of melting insulation warned her before the house caught fire.

[bluejets]

On 6/15/2022 at 10:55 AM, sometimewoodworker said:

What is a fuse?  Answer, it’s a bit of solid core wire. 

Yes but not 2.5sq mm, at least not on a gpo, maybe a 70hp irrigation pump.

Try that down here, take out the primary fuse and the supply mob will hit you with a $500.00 fee.

[sometimewoodworker]

5 hours ago, bluejets said:

Yes but not 2.5sq mm, at least not on a gpo, maybe a 70hp irrigation pump.

Try that down here, take out the primary fuse and the supply mob will hit you with a $500.00 fee.

Did you actually read the rest of the post?

 

Do you recognise gentle irony in posts?

 

In case you missed it and to be absolutely clear.

Yes, a section of 2.5sq mm wire is a fuse. Though in a ceramic tube filled with sand to absorb the flash when it blows. Of course it is not suitable as protection of any domestic supply that I know of. No I neither know nor care what the rated protection of the supply that such a fuse is designed for. Neither did I suggest that in the installation pictured it would give any protection. 
 

it is much better than the equivalent cut length of a nail that is often used in place of a clip in fuse when bodging a supply

 

Of course it will be against almost all electricity supply company rules to change main supply fuses, it may even be illegal in some countries. It’s quite likely that the same rules apply in Thailand, though as is usual here rules are differently enforced or not enforced at all

[bluejets]

Spoken like a true "dilutie would be lecky "

[sometimewoodworker]

16 hours ago, bluejets said:

Spoken like a true "dilutie would be lecky "

No kind of lecky,

 

But I certainly have an ability to write English and proof read my posts so they are at least understandable, even if misspelled. ???? 

[NE1]

Sorry to bust in on your discussion.

But does anybody know where on their electricity bill it tells you how much you are paying per unit ?

On the old bills it used to be in with the total , eg 671 units @ 3.21 baht per unit.

Now I cannot find it.

[sometimewoodworker]

10 hours ago, NE1 said:

Sorry to bust in on your discussion.

But does anybody know where on their electricity bill it tells you how much you are paying per unit ?

On the old bills it used to be in with the total , eg 671 units @ 3.21 baht per unit.

Now I cannot find it.

There is no single cost per unit  and the bill never breaks it down.

then there is the fuel tariff on all units and the standing charge the fuel tariff currently positive, it has has been negative for a while

 

if you want a rough approximation that some people are happy with then just  divide the total cost by the number of units.
 

if however you want to be exact then you need to know the tariff you are on (usually 1.1.2)