Extension Socket Incorrectly Wired

[ThaidDown]

Had need of an additional extension socket, low current, 5 switched outlets and 3 core cable (connected earth pin). Plugs will only be removed rarely so decided that a cheaper one would be ok.

Purchased one from local Tesco definitely 3 core cable and 5 switched outlets. it claimed to have 'Surge protection' and 'Noise filter' .Got it home and thought should just check the earth continuity. There wasn't any. In fact the earth pin on the plug seemed to be connected to the Neutral of the socket and vice-versa.

Opened it up and confirmed that the plug Earth pin was the Red !! wire, and was connected to the neutral, the live was white! and the neutral black!. (ok since the wiring was internal, and the plug moulded, colour code is not so important).

With a MEN system earth and neutral are connected anyway so probably no major problems, although not sure how it might affect RCD's and RCBO's though. With a TT system this effectively connects Earth and Neutral with a 0.75 sq mm cable which under external transformer fault conditions could be pretty serious, also think that there could be RCBO tripping problems.

Posted this just to inform other members that if you buy one of these they may be wrongly wired. I did not return it, just switched the E and N wires.Would have taken much longer to return to Tesco, explain the problem and exchange for a replacement, which may have had the same fault.

Image of opened unit included.

[Crossy]

Arrggghhh!

These cheapo leads are a pain in the backside! Yes, RED is often the 3rd core in local cables, and gets used as ground.

N and E swapped would cause any RCD to trip as soon as a load was applied, not a safety issue in itself.

BUT

Of course, if you didn't have an RCD and your outlet happened to be reverse polarity then your equipment metalwork would become live! Not a happy situation.

[ThaidDown]

As said, was not worried about the colour code and, yes, have used black/white/red 3 core flex.

On the plus side it did have 3 core cable so after re-soldering its ok.

Price was 299 baht, cheap but not the cheapest.

The 'noise filter' was just a couple of caps across L and N, not L-N + N-E and L-E and no inductors in series, the 'surge protector' was just a resettable trip.

Have surge and noise protection for the house so was not worried about those things.

The big question is .... was this unit a one off or are they all like that ? Not going to buy another one to find out.

[thomasteve]

As said, was not worried about the colour code and, yes, have used black/white/red 3 core flex.

On the plus side it did have 3 core cable so after re-soldering its ok.

Price was 299 baht, cheap but not the cheapest.

The 'noise filter' was just a couple of caps across L and N, not L-N + N-E and L-E and no inductors in series, the 'surge protector' was just a resettable trip.

Have surge and noise protection for the house so was not worried about those things.

The big question is .... was this unit a one off or are they all like that ? Not going to buy another one to find out.

Was there any cord clamp / strain relief fitted ? or even a knot ?

[ThaidDown]

^^

Well spotted that there was no strain relief or knot, I should have bought the luxury version, but as said in my op the plugs are to be rarely removed and the extension strip will not be hanging loose which is why I went for the cheaper one.

I added a couple of tie-wraps to the cord before reassembly to stop it pulling out.

[Familyonthemove]

Thanks for posting. I had one of these from Tesco - noticed that the plugs got really hot and I could hear arcing inside the casing - so threw it out.

May not be related to the issues you found, but it was very low cost so perhaps we do get what we pay for.

[Daffy D]

We had a thread on here about this subject some time ago

Ever since then I always open up and check the wiring any new extension unit I buy.

[thomasteve]

^^

Well spotted that there was no strain relief or knot, I should have bought the luxury version, but as said in my op the plugs are to be rarely removed and the extension strip will not be hanging loose which is why I went for the cheaper one.

I added a couple of tie-wraps to the cord before reassembly to stop it pulling out.

Cable tie wraps will work, knots are not advisable.

As there's unlikely to be any shutters on the cheaper units it's also a good idea to fit plastic blanking plugs in any of the unused sockets.

The electrical shops sell these plastic inserts for a few Baht.

[Forkinhades]

.... make one yourself?

Probably cheaper as well

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[Crossy]

I bought one of those roll-up extension leads, 3-pin outlets, Euro (Schuko) plug on the other end. Chopped the Schuko to replace with a proper local plug to reveal .... 2 core cable - grrrrrr. I should have looked more closely as the cable was clearly marked 2 x 2.5.

Got a 100m roll of 3 x 1.5 from the local electrical wholesale place (black, white, red) and re-wired the beast. The 2 core is now on a 2-pin extension for my power tools (all are Class-2).

[wayned]

I always get a "kick" out of the extensions that you can buy with three prong receptacles on one end and two prong plugs on the other! They evenb have switches and fuses with the ground pin connected to "air" which is not a good conductor.

[wolf5370]

Had several of those cheap and nasty two pin extension they sell on market stalls (often with retractable cable) melt on my, or melt the plugs. Threw all the ones I inherited away.

I did take a long bar back to Home Pro once as when I plugged it in it visibly smoked - they didn't believe me and plugged it in, it didn't smoke in the shop (possibly the lights were too bright to see it), but it got super hot very quickly and 3 of the sockets were not working at all (and they were not 3 sockets next to each other). I hadn't opened it, because I wanted to take it back and it had a Checked sticker over the screw hole (checked for the correct colour I guess!).

[Crossy]

I have a number of WonPro multi-thingys which have IEC (kettle) inlets on the end and 10A trips.

These seem to be best bang per buck as far as cost and quality go, got them at HomePro. Famous last words of course!

[thomasteve]

I bought one of those roll-up extension leads, 3-pin outlets, Euro (Schuko) plug on the other end. Chopped the Schuko to replace with a proper local plug to reveal .... 2 core cable - grrrrrr. I should have looked more closely as the cable was clearly marked 2 x 2.5.

Got a 100m roll of 3 x 1.5 from the local electrical wholesale place (black, white, red) and re-wired the beast. The 2 core is now on a 2-pin extension for my power tools (all are Class-2).

What would be the best method of wiring those core colours (black, white, red) as black is recognised as 'hot' (live) in USA and white neutral that leaves red as earth. Otherwise it could be red for live, black neutral and white as earth ?

[Crossy]

Theoretically, Thailand uses the US colour code.

Using red for earth seems counter intuitive, but it allows the other colours to be 'correct', so that's what I've been doing whenever I've had this type of flex.

Stick some green tape or sleeving on it if you're worried. Western codes prohibit the use of the green / green-yellow core for anything other than ground (even if sleeved), but say nothing about you having to use green / green-yellow for ground.

[thomasteve]

Theoretically, Thailand uses the US colour code.

Using red for earth seems counter intuitive, but it allows the other colours to be 'correct', so that's what I've been doing whenever I've had this type of flex.

Stick some green tape or sleeving on it if you're worried. Western codes prohibit the use of the green / green-yellow core for anything other than ground (even if sleeved), but say nothing about you having to use green / green-yellow for ground.

That's probably the best option, as using red for live, black neutral, could be unsafe if red is more commonly used for earth conductor.

[h90]

I bought one of those roll-up extension leads, 3-pin outlets, Euro (Schuko) plug on the other end. Chopped the Schuko to replace with a proper local plug to reveal .... 2 core cable - grrrrrr. I should have looked more closely as the cable was clearly marked 2 x 2.5.

Got a 100m roll of 3 x 1.5 from the local electrical wholesale place (black, white, red) and re-wired the beast. The 2 core is now on a 2-pin extension for my power tools (all are Class-2).

I bought a cable for the computer, the normal cable 2 flat pins and one round for earth and the connector for the PC power supply on the other side.

And for no reason I measured earth pin to the earth that connects on the power supply....nothing.

I cut the cable: just 2 core.

Local computer shop had no others......Just unbelievable...

[Daffy D]

Local computer shop had no others......Just unbelievable...

No it's not

[h90]

Local computer shop had no others......Just unbelievable...

No it's not

I didn't go there myself, I sent one staff. But I explained the issue exactly and had the feeling that it was understood.

Still it is possible that the computer shop, just told "mai mee" to that weird whatever cable that farang wants....they may don't know about the difference, as they look the same (beside they are bit thinner).

It is a computer shop...they aren't supposed to be technicians.....

(a bit outside from the center of Bangkok).....