Domestic Electrics (again!)

[nobber9999]

This topic has probably been covered before although its really two topics. Firstly, having just had my house rewired with 3 core cable and appropriate earthing and fuse box, I needed to put in a new hot water shower unit which was I simple task or so I thought. Having thrown the breaker for the shower sure enough, the display didn't work but before playing with any wires I just did a basic neon screw driver test on the feed wires. To my dismay, I found not only the live wire to still be live but also the neutral to be live. At least there was an earth connected which was not live. Can anyone enlighten me on this before I enlighten myself by sticking my fingers where they shouldn't be????

Secondly, a more simple item. A lot of larger appliances these days come with a fused on plug which has a hole where the earth pin should go but its not there. If my memory is not failing me, it was not long ago when the earth pin was supplied but not pushed into the plug so as not to fool the locals. The third pin no longer is supplied but where on earth can I find a supply of these rare items??? Before anyone mentions it, I have checked the appliances to make sure that the earth is connected at the consumer unit end as well as the plug end and yes they are!!!

Looking forward to any help anyone can give.

[david96]

Do not use a proximity detector (neon test screwdriver) as the sole means of checking supply.

Use a VOM or a solenoid type voltage tester (Square D) to check supply and polarity. You must prove your neutral.

Procedure. Active (line) to Neutral 220/240 volts. Active to Earth 220/240. Neutral to Earth 0 volts.

Visual check of all connections also. All switches must operate in the active conductors.

[kelvinj]

If there is a break in the neutral line you would get the symptoms you describe, assuming that you are testing the voltages at the shower unit terminals, you are effectively looking through the shower heater coil at the supply voltage, this will only fall to zero on the neutral side if the neutral is connected.

[lopburi3]

Electric showers have a built in RCD breaker that also has to be on to work. As not sure what you threw or checked would advise you hire someone to check rather than take a chance yourself. It is just not worth the risk and a meter will likely have to be used and they can be easy to short in open circuits.

The new plugs used here are on the units because they are designed for export to markets where they have the side ground straps or where the pin is in the outlet rather than the plug. There is an adapter sold in Home Pro to provide the pin but it does not fit into the plug hole but obtains ground from the side straps. Unfortunately two of these will not fit the standard wall outlet so I am finding myself replacing the plugs more often than not.

[nobber9999]

Electric showers have a built in RCD breaker that also has to be on to work. As not sure what you threw or checked would advise you hire someone to check rather than take a chance yourself. It is just not worth the risk and a meter will likely have to be used and they can be easy to short in open circuits.

The new plugs used here are on the units because they are designed for export to markets where they have the side ground straps or where the pin is in the outlet rather than the plug. There is an adapter sold in Home Pro to provide the pin but it does not fit into the plug hole but obtains ground from the side straps. Unfortunately two of these will not fit the standard wall outlet so I am finding myself replacing the plugs more often than not.

[nobber9999]

Thanks to everyone for your assistance. We managed to get hold of the guy the Electric Company use for connections etc and it turns out that he managed to swap our positives and neutrals around when we recently upgraded our supply meter box. Its amazing the effect that has especially when he almost got a wallop from our consumer unit after throwing the mains supply to off!!! For anyone interested, if you have a surge protector fitted next to the RCBO it usually has a small green power light displayed and this should turn off when the mains power switch is set to off. In my case the light stayed on when power was off or on. Everything is now back to normal with only one terminal per socket reading live and thats using a proper meter doing a hot test on all three terminals.

If anyone is interested I have found a supplier with a website who can supply 13amp 3 core cable complete with welded 3 pin plug at one end and the other just awaiting connection. The wire a about 1.5m so should be OK for most appliances. Their website is http://www.es.co.th

Thanks again to all who replied.

[david96]

Thanks to everyone for your assistance. We managed to get hold of the guy the Electric Company use for connections etc and it turns out that he managed to swap our positives and neutrals around when we recently upgraded our supply meter box. Its amazing the effect that has especially when he almost got a wallop from our consumer unit after throwing the mains supply to off!!! For anyone interested, if you have a surge protector fitted next to the RCBO it usually has a small green power light displayed and this should turn off when the mains power switch is set to off. In my case the light stayed on when power was off or on. Everything is now back to normal with only one terminal per socket reading live and thats using a proper meter doing a hot test on all three terminals.

If anyone is interested I have found a supplier with a website who can supply 13amp 3 core cable complete with welded 3 pin plug at one end and the other just awaiting connection. The wire a about 1.5m so should be OK for most appliances. Their website is http://www.es.co.th

Thanks again to all who replied.

It is quite obvious that the person who connected the supply to your installation was not competent as a polarity test was not carried out. You are fortunate that you or others were not severely injured or killed.

(This is where the TT system is safer)