Low Earth Voltage in bathroom from bonded fittings

[snowhead]

The tingle is when I'm standing on a tiled floor near the shower.

You haven't got underfloor electric heating by any chance have you?
Or was the bathroom floor covered in nailed down plywood before the tiles were put down?

 

[Kris Dor]

Hi,

I have found out this since:
If the earth is disconnected from the shower unit the voltage on the shower hose goes up to 109V AC
When this happens the 3amp fuse in the switched spur doesn't blow and the RCD protecting the Ring main the spur is on doesn't trip either.

Needless to say I've turned it off at the double pole switch.

Is the shower knackered? Why didn't the fuse or RCD trip?

No underfloor heating, yes it is AC voltage, there are undoubtedly a few nails in the floor boards from when the house was built.

 

[snowhead]

If the earth is disconnected from the shower unit the voltage on the shower hose goes up to 109V AC
When this happens the 3amp fuse in the switched spur doesn't blow and the RCD protecting the Ring main the spur is on doesn't trip either.Why didn't the fuse or RCD trip?

There's no reason for the fuse to blow or RCD to trip, there's voltage there, but no current flowing, apart from whatever is flowing through the meter.

 

[static zap]

You have created a potential divider , probably via capacitive coupling half way between N=0V AC
and Live =240 ..then lost a little due to the meter .
(not a very safe test) esp if nervous !
Leakage currents are just that , small currents doing no harm escaping to earth .
( Unless a fault occurs without Earth attached = danger)

 

[Wilko]

Agree with above - but don't use the shower without earth connected as manufacturer intended

 

[CACJL]

I have a hot/cold feed power shower in bathroom, shower frame and a radiator near by.
I'm measuring the voltage difference between the three things and getting the following and wondered if anyone could help. Had two sparky's out who have not thrown any light on it so far.
Shower hose (metal) to radiator 0.2v
Radiator to Shower frame 2v

When I run the shower for 2-5 mins I get these readings
Shower hose (metal) to radiator 5v
Radiator to Shower frame 12v

This voltage then very slowly drops back down to earlier figures over the course of mins/hours rather than seconds (in 5-10 mins it would drop from 12v to 10v)

I have this: Bonding from rad to both inlet pipes of shower
I was advised to do this which is now done: Bonding from earth in shower unit to the pipework feeds and supplementary bonding from pipework to two upstairs light rings which was advice sparky got from NIC

The shower is hot/cold so just a pump from a spur on ring main protected with switched fused 3a and RCCB on ring main circuit

If I switch off the bathroom lights the first 0.2v reading prior to running shower might drop from 0.2v to 0.1v

Nothing on the CU has tripped but there is a tiny spark when sparky took off an Earth from the (rail?) in the CU while he was looking at it.

No single circuit seems to be the cause of the low voltage readings but if everything is off on the CU the reading is 0v.

Any help ideas would be appreciated .
Cheers
Kris

I have a hot/cold feed power shower in bathroom, shower frame and a radiator near by.
I'm measuring the voltage difference between the three things and getting the following and wondered if anyone could help. Had two sparky's out who have not thrown any light on it so far.
Shower hose (metal) to radiator 0.2v
Radiator to Shower frame 2v

When I run the shower for 2-5 mins I get these readings
Shower hose (metal) to radiator 5v
Radiator to Shower frame 12v

This voltage then very slowly drops back down to earlier figures over the course of mins/hours rather than seconds (in 5-10 mins it would drop from 12v to 10v)

I have this: Bonding from rad to both inlet pipes of shower
I was advised to do this which is now done: Bonding from earth in shower unit to the pipework feeds and supplementary bonding from pipework to two upstairs light rings which was advice sparky got from NIC

The shower is hot/cold so just a pump from a spur on ring main protected with switched fused 3a and RCCB on ring main circuit

If I switch off the bathroom lights the first 0.2v reading prior to running shower might drop from 0.2v to 0.1v

Nothing on the CU has tripped but there is a tiny spark when sparky took off an Earth from the (rail?) in the CU while he was looking at it.

No single circuit seems to be the cause of the low voltage readings but if everything is off on the CU the reading is 0v.

Any help ideas would be appreciated .
Cheers
Kris

 

[CACJL]

Is your earthing system TN-C or TN-C-S ?

 

[Toneyz]

This reminds me of when years ago house bashing house been fully tasted ,RCD to sockets only split board supplementary bonding between hot cold ,rad and upstairs lighting circuit. The homeowner complained regarding getting tingle between rad and shower (not electric).Measured it and was 12v did insulation resistance test and found low reading on downstairs lights located it to outside lighting cable that where installed outside light taken down ,cable end cut and tapped up that when rained dampness between live and earth not enough to trip mcb.

 

[Midwest]

Don't just lurk around in the background bak1950, post some replies or start some threads, after all its been over 7 years. By the way sparksburntout is the head teacher on spelling mistakes or bad grammar.