New wiring into existing house

[Na Fan]

I have a quick question since it's now the second time I'm faced with this. Existing house, has only 2-plug power outlets in the house, nothing is earthed.

Are electrical wires in Thai houses not laid inside plastic pipes inside the walls? Can you not simply add one without tearing the walls open?

I've done this previously, in Europe, and used the attached plastic wire to push new wires in. Is this not how you do it around here as well?

Na Fan

[lopburi3]

Normally wire is on surface - when inside cement it would normally be in plastic conduit. Walls are mostly solid here but non-supporting so they could cut channel and run new conduit and cover - but remember beams are supporting and this will likely not be an option for them.

[bankruatsteve]

If the wires are in the wall, chances are they are protected with the yellow conduit. You could open a receptacle and check. If you then have access to the space above, it is likely that you could add the ground wire to most places.

[lopburi3]

But you might want to replace the likely undersized current wire.

[Crossy]

Wiring snakes or fish are readily available from the specialist stores, the fun part will be getting your new earth wire into the conduit.

As others have noted, it's also worth checking on the size of the existing wiring and either replacing it if undersize or reducing the breaker size to compensate.

[wayned]

I agree on all plugs being earthed and the proper upfront RCBO protection and I most likely will get slammed for posting this, BUT: Get realistic!

Before you rewire your whole house for earthed sockets take a look at what you're are going to plug into them! I have over 120 sockets in my house, some are earthed and some aren't. The ones outside, the ones in the kitchen and the ones outside the bathrooms are earthed, most of the others are not. I wired the house myself 17 years ago, and rewire as required, 3 x 2.5mm Romex was not available where I live when I built my house. I can count on two hands the number of appliances that actually have earthed plugs, one of the three fridges, the counter top convection oven, the deep fryer, the microwave, the UPS for the computer, the monitor, one of my two welding machines and the computer. The water pumps have external earthing wires that I have connected to the earth pin but that's all; 10 appliances and over 120 sockets.

Before you go to the expense and drastic cutting of new channels in existing walls to add the third wire, evaluate what you have and come up with a realistic plan of what you need!! I would opt for safety and functionality and not rewire the whole house unless the existing two wire installation is defective or inadequate.

[lopburi3]

unless the existing two wire installation is defective or inadequate

Which it likely is - amazing the hair thread size wire that was standard for construction here a few decades ago when a table fan was likely going to be the high wattage appliance.

[wayned]

That's exactly why I said "defective or inadequate".

But it's not only house wiring, sometimes it's the wire connected to the device that you are going to plug in. I recently bought a new ARC welder. It's a 250 watt unit with input ratings of 15.2kw at 35% duty cycle. The manual clearly states that the input wiring should be at least 10mm2, agreed.

The unit was supplied with a power cord attached connected to a Schuko plug. The first thing that I checked was if the earth pin was actually connected to the case, it was. However the wire size of the installed power cord was only 2.5mm2 and the manual said at least 10mm2. So, since it had a Schuko plug, it could have come out of the box and be immediately plugged into any Thai 2 pin socket which could be wired with 1mm2 wire. Turn it on and wait for the smoke!!

It's been rewired with the proper sizeVCT cable, 3C x 10mm2, and now has a 32 AMP water proof plug that can be connected to my previously wired distribution systemand used with my 10mm2 extension cord which is also terminated withn32 AMP connectors..

I think that the reason that many appliances are supplied with Schuko plugs is that they can be plugged directly into the Thai two wire sockets witout adapters. I think the rthe Schuko plug is the only three wire plug that can be directly used in the two pin sockets without an adapter.

[lopburi3]

Believe true - that plug requires no change to fit most Thai outlets - not there care there is no ground protection! Have also bought some IEC connecting cords from China with amazingly bad wire - some so bad would not even work out of package - others just a thread of copper which will quickly overheat (and best luck burn out as a fuse rather that catch fire). It is not just a Thai problem - but allowing this junk to be sold is a Thai issue. House wiring standards have greatly improved - but what is being sold to plug into this is often worse than years ago as corners are cut to save money.