Feeling electricity while showering

[fusionx]

Before year and a half or two I started noticing that while taking a shower I can feel some kind of an electricity when touching the faucet or when holding the shower head (I have a metal bathtub which has the shower feature).
For the first couple of months only I could feel this (sometimes I wouldn't feel it at all), but later my parents could feel the electricity too. Later it seemed that the electricity became stronger (from tingling to "buzzing" or something) so I was only taking baths.
Finally we hired an electrician who told us that the water heater (with a tank, and yes it was always off when I was showering) had some loose wires or wasn't connected to earth (can't remember exactly), so he fixed it.
And now, like a year later I once again felt weak electricity when I was taking a shower. We hired another electrician who said that there was a voltage between the faucet (shower) and the bathtub of 6 volts.
He than connected the tub with a 4mm diameter wire to the earth and claimed that the problem was fixed and he equalized electric potential between those two.
He was also checking the earthing and I assume it was ok since he wasn't mentioning a fault of that to us.
So I'm interested if this really solved the problem and is it safe now?

We don't have a GFCI (quite old house), so the electrician said that he would come these days to install one but only for the bathroom (he said that he couldn't for the whole house, I guess the problem is physical).
So if the potentials are equaled and the earthing is OK, what's going on with that small electricity which previously preferred me over the earthing?

 

[JohnD]

I don't know what electrical installations are like in your country. This is a UK site.

It is not unusual for electricity to leak in heating appliances, or in appliances containing water.

In the UK, we (usually) use a method called Supplementary Equipotential Bonding, and connect all the metallic services (water pipes, drain pipe, heating pipes etc) to the earthwire of all electrical circuits entering the bathroom. That means that even if there is a fault, you will at least not be a able to get a shock from touching two items in the bathroom, because they will all be at the same potential. It sounds as if your electrician has done something similar.

you can read more about it on http://www.diynot.com/wiki/electric...l_bonding:supplementary_equipotential_bonding

 

[fusionx]

So basically the problem with a faulty appliance (or any device) persists, but it's not a life threat anymore (or any human threat for that matter)? That's fair enough for me.

And the faulty electric device had to be on while I was showering and feeling that electricity? Does this rule out the laundry machine or the water heater since they were off at those times? Basically, after he installs the GFCI for the bathroom and if nothing trips it, that would mean that the problem comes from outside of the bathroom?

Could the bathroom GFCI be tripped at all from a faulty device from the kitchen for example? I'm thinking not, because if the potentials are equal in the bathroom now there's no longer discharge on me (just guessing).

I assume that it wouldn't be such a short job to track where the fault comes from, so this electrician is just trying to cut his job here and still make it safe.

Thanks for your help,

 

[JohnD]

GFCI is not a term we use. What does it do?

I cannot guess where the fault originated. It might have come from any circuit or any appliance connected to a water pipe. Unless the appliance is unplugged (not just switched off) you cannot be sure that it is not the source. It is even possible that the fault originates outside your house, and is caused by an appliance or wiring fault somewhere else, that is travelling along metal pipes or cables. The UK approach is to Main Bond all metallic services where they enter the house, so that it should not be possible to get a shock from something outside. This uses quite large cables (10mm sq) which will take a large current in the event of a fault. We bond the incoming electrical supply to Gas and Water metal pipes, and to Oil and Air Con pipes (if present). If there is not a good earth on the electrical supply, we also bond to an Earth Rod stuck in the ground.

If the fault in the appliance is very large, it may trip the MCB or burn out the fuse, but for a large appliance it might take a large current and a considerable time o do this.

Unsolved Earth Leakage faults tend to lead to tripping of RCDs and it can be difficult to trace the fault that is causing it.

 

[fusionx]

Sorry, my bad RCD = GFCI.

In the United States and Canada, a residual current device is also known as a ground fault circuit interrupter (GFCI), ground fault interrupter (GFI) or an appliance leakage current interrupter (ALCI).

Yeah but when the first electrician came and claimed to have fixed the problem, it was actually gone for a year. So basically,
- electricity feeling when taking a shower
- electrician comes and fixes something at our home
- problem gone for a year. (that kinda indicated to me that the problem came from our house)
- very small tingling after, not constant
- since the 2nd electrician equaled the potentials I took one shower and felt nothing

 

[fusionx]

Actually I'm mostly interested about the electric shock threat? If he grounded the tub like the water pipes and the water heater is it safe to use the shower?

 

[JohnD]

I can't tell from here.

Bonding all the pipes, and the earth wires of all the circuits, is a good start.

Also verify that the heater is properly earthed; and that the earth wires in the appliance, cables, consumer unit and incoming supply are all connected. In old installations, especilly if they have been worked on over many years by many people to many standards of skill, this may not be the case.

The next step woulkd be to use an Earth Loop Impedance tester, which is very accurate, but is not a DIY tool. A High Street Multimeter is not one tenth as accurate and cannot safely be used to test under load,