What Should Happen When You Press The "test" Button On An Elcb ?

[whatawonderfulday]

Just bought the new house, Thai electrics ( say no more ). changing a light fitting for a ceiling fan with the lighting circuit MCB in the off position and got a little shock !. So switched off the main breaker and completed installation.

Not being an electrician I assumed that when pressing the "TEST" button on the ELCB in my consumer unit it should trip the circuit out - am I right or wrong pls ? Anyway when I press the "TEST" button nothing happens which strikes me as not quite right.

So can anyone reccommned a good quality, European standard electrician in Bangkok I could use ?

[Crossy]

You are correct, pressing the 'test' button should cause the unit to turn off. Note that the button only works when the power is on, so if you've opened a breaker upsteam of the ELCB nothing will happen.

It's not unknown for L and N to get transposed, in which case opening the MCB will open the neutral leaving the live to bite. On an unknown installation either use your trusty neon-screwdriver or open the main breaker to ensure all is dead.

Sadly I can't recommend a BKK based sparks, although I'm sure others on this board will be able to

[whatawonderfulday]

You are correct, pressing the 'test' button should cause the unit to turn off. Note that the button only works when the power is on, so if you've opened a breaker upsteam of the ELCB nothing will happen.

It's not unknown for L and N to get transposed, in which case opening the MCB will open the neutral leaving the live to bite. On an unknown installation either use your trusty neon-screwdriver or open the main breaker to ensure all is dead.

Sadly I can't recommend a BKK based sparks, although I'm sure others on this board will be able to

Many thanks for that. I actually got the shock from the braided metal the wires were in. Never know whether the white or blue is live either, seems to depend on installer (cowboy).

[Crossy]

Many thanks for that. I actually got the shock from the braided metal the wires were in. Never know whether the white or blue is live either, seems to depend on installer (cowboy).

The (alleged) Thai standard code is:-

Black - live

White - neutral

Green - ground

A little poking around in you distribution box / consumer unit should give you a hint as to what has actually been used. The wires coming out of the bottom of the MCBs should be the lives.

The fact that you got a tickle off the conduit suggests that it's not grounded and is picking up stray current by capacitive coupling, not dangerous in itself but not desirable. Ground the conduit if possible.

[lopburi3]

It could also be he was the source of the voltage and the conduit discharged the static electric. I doubt he tried a second time to check.

The RCB, if Safe-T-Cut, may have an adjustment that can be used to bypass protection. Be sure that is not set. If not and you have power and the test does not trip you need to have it checked out as it could be defective.

[Crossy]

The RCB, if Safe-T-Cut, may have an adjustment that can be used to bypass protection. Be sure that is not set. If not and you have power and the test does not trip you need to have it checked out as it could be defective.

Good point Lop, must remember these stupid things have a bypass setting.

[whatawonderfulday]

Many thanks for that. I actually got the shock from the braided metal the wires were in. Never know whether the white or blue is live either, seems to depend on installer (cowboy).

The (alleged) Thai standard code is:-

Black - live

White - neutral

Green - ground

A little poking around in you distribution box / consumer unit should give you a hint as to what has actually been used. The wires coming out of the bottom of the MCBs should be the lives.

The fact that you got a tickle off the conduit suggests that it's not grounded and is picking up stray current by capacitive coupling, not dangerous in itself but not desirable. Ground the conduit if possible.

Thanks again I'll take your advice