Any Good Electricians Reading This? Need Advice

[tattoodrob]

Hi, i have a condo(2nd floor) i rent out and over 6 months ago the renter reported he got an electric shock from metal handle for water supply to shower, we had it installed by electrician(haha) ages ago, i had a look inside shower box and saw it had earth wire so thought i would just change the shower as was oldish and solve the problem. After changing the shower we discovered the earth stops at the circuit box so it doesnt really have an earth and renter was still getting a buzz type shock. After a couple more electricians came we ended up buying a 2m copper rod to earth just the shower, i thought this would solve the problem...no.....still getting shock and no thai guys any idea what to do next so i thought i would change the metal water supply tap and the metal hose etc all to plastic so the electric current would be stopped.....doesnt cure the problem but thought it would save electric shocks.......wrong......they have now reported that they still get a shock from the small metal part in centre of plastic tap and the metal tap at the sink.....i have no idea what to do next, dont wanna kill them but had 3 or 4 different workers have a go. where can i find someone who would be able to help, i dont wanna kill my tennants, the condo maintenance guy aint got a clue and condo management not helpful as its not them getting a shock!!!

Any advice welcome, im guessing its nothing to do with the shower and that maybe a live wire is getting to the water supply near my room , nobody else seems to be having a problem in the building.

[Crossy]

Hmmmm, sounds like you need to investigate these 'shocks'.

Get out your neon screwdriver and poke around all the remotely metallic bits. Try touching the taps whilst you've got your finger on the neon.

How good is your earth (second floor condo), if you have galvanised pipes they should make a pretty good ground.

It's possible that the pipes are hot from another source, check the voltage between your ground and the taps.

Linking all the metal together (equipotential bonding) likely prevent any more shocks, but you need to find where the volts are getting in.

Edited February 16, 2009 by Crossy

[Cuban]

How good is your earth (second floor condo), if you have galvanised pipes they should make a pretty good ground.

It's possible that the pipes are hot from another source, check the voltage between your ground and the taps.

I would be surprised if the water pipes are galvanised and suitable for carrying an electrical earth for the entire run from bathroom to the ground outside, I would not trust them without seeing the entire run. Difficult unless you monitor construction. Are there building maintaince risers that you can look into - see if pipe runs are plastic/metal?

Is the shower still giving a shock while it is not powered or not running? (even disconect it's electrical supply and check again)

i had a look inside shower box and saw it had earth wire.... After changing the shower we discovered the earth stops at the circuit box so it doesnt really have an earth and renter was still getting a buzz type shock. After a couple more electricians came we ended up buying a 2m copper rod to earth just the shower, i thought this would solve the problem...no

Have you proved that the earth wire that disappears into the wall/conduit at the shower end is fully connected through to the circuit box? I have seen wiring in Thailand that looks nice in the junction box - but turns out to be a 5cm stub that is just tucked into a conduit that goes no where and is for decoration only.

Is your 2m earth rod in soil that is not too dry, is it doing it's job.

You saying that you have replaced metal pipes with plastic and the shock remains: I'm wondering if you are getting the shock via 'hot' water, is the pump that is pressurizing your system faulty? I would expect that people encount a shock when showering, maybe not notice it? Wouldn't hurt to check the pump.

--------pause--------

I'm thinking that maybe your earth rod (and or it's cabling) is high impedance and that the earth connection between the shower unit and the circuit box is where the fault is. If you disconnect the earth from the shower unit does the shock remain? ( I would test twice - once disconnect at shower end and test - then reconnect that earth and test with the earth removed at the circuit box end.)

What else is earthed via that circuit box, I'm thinking fridge, air-con unit? Fairly easy to confirm the shower fault is still there - then unplug each other device in turn and recheck the shower for a shock. You can do this without trying to explain the process of elimination to a Thai electrician.

HTH.

Edited February 17, 2009 by Cuban

[tattoodrob]

How good is your earth (second floor condo), if you have galvanised pipes they should make a pretty good ground.

It's possible that the pipes are hot from another source, check the voltage between your ground and the taps.

I would be surprised if the water pipes are galvanised and suitable for carrying an electrical earth for the entire run from bathroom to the ground outside, I would not trust them without seeing the entire run. Difficult unless you monitor construction. Are there building maintaince risers that you can look into - see if pipe runs are plastic/metal?

Is the shower still giving a shock while it is not powered or not running? (even disconect it's electrical supply and check again)

i had a look inside shower box and saw it had earth wire.... After changing the shower we discovered the earth stops at the circuit box so it doesnt really have an earth and renter was still getting a buzz type shock. After a couple more electricians came we ended up buying a 2m copper rod to earth just the shower, i thought this would solve the problem...no

Have you proved that the earth wire that disappears into the wall/conduit at the shower end is fully connected through to the circuit box? I have seen wiring in Thailand that looks nice in the junction box - but turns out to be a 5cm stub that is just tucked into a conduit that goes no where and is for decoration only.

Is your 2m earth rod in soil that is not too dry, is it doing it's job.

You saying that you have replaced metal pipes with plastic and the shock remains: I'm wondering if you are getting the shock via 'hot' water, is the pump that is pressurizing your system faulty? I would expect that people encount a shock when showering, maybe not notice it? Wouldn't hurt to check the pump.

--------pause--------

I'm thinking that maybe your earth rod (and or it's cabling) is high impedance and that the earth connection between the shower unit and the circuit box is where the fault is. If you disconnect the earth from the shower unit does the shock remain? ( I would test twice - once disconnect at shower end and test - then reconnect that earth and test with the earth removed at the circuit box end.)

What else is earthed via that circuit box, I'm thinking fridge, air-con unit? Fairly easy to confirm the shower fault is still there - then unplug each other device in turn and recheck the shower for a shock. You can do this without trying to explain the process of elimination to a Thai electrician.

HTH.

i guess what im really after is a phone number of somebody that can finally sort this out as the average builder/maintenance guy cannot sort and neither can i.

It seems the water could be the conductor of the electricity , i dont think anything else is earthed back to the box.....the earth from box to anywhere was missing till i had about 20m of wire and copper pole added,i didnt see where the pole went as wasnt there but guess its in dry earth ifhe actually put it in but i guess it actually doesnt work and as the person is closer than the pole then they get the shock.

Maybe il have it rewired to try and fix the problem or if anyone can supply me with a pone number of a specialist here if there is such a thing!!!!

[tjo o tjim]

It sounds to me that you actually have a short to the water supply somewhere. I would try and turn off power to the condo unit first and see if the metal bits are still providing a shock. If this is happening then nothing you do within the condo will help, and could actually make things more dangerous.

The other thing to consider is if your utility supply is actually a MEN system... you might need to eliminate the ground wire to make it as safe as possible.

Is this just a two story building?

[Crossy]

I was thinking something similar, possibly a L-E fault somewhere to the crappy ground (water pipes perhaps). The OPs extra ground point actually introduces a hazard by being at true ground potential

If our OP gets a neon-screwdriver he'll be able to verify which metalwork is biting without actually having to receive a shock

Shocks from something that should be grounded are always worrying.

Like most of these situations actually SEEING the installation makes life soooo much easier, being on the end of a non-techies description can make life 'interesting'.

Edited February 18, 2009 by Crossy

[mdechgan]

If the ground is separate and installed correctly, make sure all the wires are connected.

I think the leak is from another room somewhere along the pipeline. Even if you ground your handle doesn't necessarily mean there is no leak and the ground wire doesn't offer the least resistance.