Slight electrical shock from metal shower hose?

[FACTOR]

Hi. A 5 baht coupling broke on my shower hose (hose is that flexible metal type; cheap aluminium I suppose) so I bought a whole new set --- hose with shower head -- and when I hooked it up to the hot water shower box there is now one of those low grade electrical shocks running through it.

I was able to take it off despite the low shock and now just taking bucket baths. But what's up with this? This did not happen before. And I'm sure the hot water shower box is grounded. Help!

Thanks.

[Crossy]

Has anything else changed?

Does the 'shock' still appear if the breaker for the shower is turned off at the distribution board.

What is the water connection to the shower hose made of where it leaves the shower?

Is the new 5 Baht coupling identical (same material) as the one that broke?

Do you have a means to measure voltage?

Do you have an RCBO / Safe-T-Cut?

It is quite possible that under certain conditions a MEN connected ground (the shower) can be several volts above 'real' ground (the shower floor). Normally not an issue, but under certain conditions you could feel a tingle.

Verify the shower unit really is grounded. Does the shower have its own local ground rod, or does it connect back to the distribution board ground?

[lopburi3]

Actually many of the cheap chrome finish hose are plastic rather than steel - also at connection to heater it is normally a plastic fitting but if large connector it might make contact with metal on some but do check all of the above and advise. Have seen specific warnings not to use metal hose on Japanese type water heaters (but if good ground and RCD they should be OK and wife insists on them as much more flexible).

[gandalf12]

Sounds like you have left thee earth connection, assuming there was one before, disconnected. what you are feeling is a leakage current. May not be much but you need to get it taken care of it could be serious in the future

[Crossy]

Yup Gandalf. I suspect something is awry with the earthing.

That said, it's not unknown for people to perceive that they've received a shock without have actually had one.

I've done it myself in our newly built home, despite knowing that the shower heater was correctly grounded, we have RCD protection, all PVC pipes and the building steel bonded to the system ground I still 'felt' a tingle which defied any attempts to measure it.

[bankruatsteve]

In a previous place, I used to get a tingle from the shower connected to a multi-point heater that I know was connected to ground. Never did figure that one out.

[gandalf12]

Yup Gandalf. I suspect something is awry with the earthing.

That said, it's not unknown for people to perceive that they've received a shock without have actually had one.

I've done it myself in our newly built home, despite knowing that the shower heater was correctly grounded, we have RCD protection, all PVC pipes and the building steel bonded to the system ground I still 'felt' a tingle which defied any attempts to measure it.

Obviously you have an electrical background like my self. When we had a house built off HW 36 in Pattaya I supervised all the electrical installation and made sure the earthing was to UK standards. Still had a Safety Cut put in as well. You cant take a chance with electricity as you know

[Crossy]

Thailand is (at least theoretically) TNC-S with MEN (PME to us Brits).

Unfortunately, due to the haphazard implementation some neutrals can get well above true ground potentials, if this is also your TNC-S "earth" to an appliance it is possible for the appliance metalwork to be quite a few volts above true ground. You can check using a 'big screwdriver" in the lawn and measuring between it and the ground bar in the distribution board, it should be no more than 10V AC.

If you are now stood on a wet floor which has a reinforcing grid (re-bar) which is connected to the rest of the building steel (and thus at true ground potential) it is possible that you will perceive the potential difference between your feet (on the grounded floor) and your hands (holding the earthed shower handset).

This is not normally a hazard, but if it's causing worry bond your building steel (the roof structure works well) to your electrical ground. This will create an equipotential zone within the house and you will (should) not be able to detect a potential between any two points.

[FACTOR]

Thank you for the replies. I will try to follow up on your advice and will let you know how it works out.

The problem is I cannot find a reliable electrician in my part of the woods. What you have all said is WAY above my level of knowledge and I am confident WAY above the local "electricians'" heads.

Wish me luck.

[Gary A]

As was mentioned. The first thing to check is to see that the shower unit is earthed to a ground rod. If it is not, buy a ground rod at least a meter long. Pick a wet spot and drive it in. Quite often you will have a spot where a downspout is draining. Buy the proper length of green copper wire, connect it to the rod and run it to your shower unit. It's a simple thing. I have ground rods on each corner of the house and two for the garage/workshop.

[xylophone]

A friend had something similar a while back and nothing would stop it..........then the pump motor was checked and it wasn't earthed. Earthing it stopped the problem. Go figure!