554.3.2 - p212 18th Ed Question

[John-]

Hi

This reg relates to elements of water heaters that are not insulated, not electrode based water heaters. It states that a separate earth must be provided in addition to the CPC. It seems that some showers also follow this principle.

Anyone know of any modern day domestic showers that use this method? If so, do the manufactures state that a separate earth should be used or state that the water is heated with an uninstalled element?

Also, how can this even work without the risk of electric shock - i may have answered my own question and that maybe this is an industrial practice in a controlled environment only? But still it seems dodgy?

Cheers

John

 

[Silly Sausage]

Also, how can this even work without the risk of electric shock

Can't see why.
It [the reg] reads that such water heaters should have their own dedicated (via the supplying water pipe) Earth back to the MET.
I wonder if the water Equi-bonding cable counts as the required connection? Don't see why not myself.

 

[John-]

Surely there would be some flow of current back to earth - how could you use an RCD on the circuit? Everything would have to be double pole even in MCBs in the Dis board. I wouldn't want to take a shower in water i know is in contact with 230vAC. When it goes wrong, i may be in its path?

 

[Bobster]

Doubtful that you will find this method of water heating in a domestic environment.

Most likely in industrial installations an the circuits will most likely not need RCD protection.

 

[westward10]

Look for suicide showers on YouTube there you will see some examples.

 

[Wilko]

Hi - these uninsulated heating elements can be found in shower heads in some countries and have been termed "suicide showers" by some. They've an exposed element which heats the water by direct contact. They do kindly put an earth wire in the water to try to drain off (pardon the pun) any leakage (there 'e goes again) but it just doesn't seem right to me. Here's a pic from the net just for fun.

 

[Bobster]

This is what I was imagining, who in their right minds would use a shower like that?

Still, they do say ignorance is bliss.

 

[John-]

Thanks all, answers my questions enough i think - such an odd thing to have in the IEE though.

 

[Bobster]

Thanks all, answers my questions enough i think - such an odd thing to have in the IEE though.

7671 covers all aspects if installation though, so quite applicable to industrial water heaters like I posted about.

 

[ackbarthestar]

This is what I was imagining, who in their right minds would use a shower like that?

Still, they do say ignorance is bliss.

That looks like an electrode water heater as opposed to an uninsulated water heater...

 

[Bobster]

That looks like an electrode water heater as opposed to an uninsulated water heater...

One and the same no?

 

[ackbarthestar]

Would that be a yes no or a no yes?
They are different
One employs the water as the heating element - electrode boiler usually industrial 3 phase at LV or MV. 554.3.2 and 554.3.3
and the other runs a nichrome wire, or similar, through the water and as long as the water exits the shower head as a sprinkle and not a continous flow then it is unlikely to give the person showering an electric shock - 544.3.1 and 554.3.4

 

[westward10]

Dodgy trade pic's for your amusement! - https://www.electriciansforums.co.uk/threads/dodgy-trade-pics-for-your-amusement.101061/page-6
See #77

 

[ackbarthestar]

Well, at least the clown could have used 4.0mm2 bonding .....

To add... are all those installs real or a figment of somebody's furtive imagination?