Grounding for shower heater

[bkkbarnstormer]

Moving into a condo which will have a new shower heater fitted. It is an old building and the wiring to the heater itself appears to only include red and black wiring is no earth cable. 

 

Any suggestions on what we should do to ensure the shower heater is fitted as safely as possible by the building maintenance people?

[tropo]

That's a good idea. My wife was zapped in the shower at our last rental. We got the owner to put in a separate breaker switch. She never got the courage up to use that particular shower again no matter how I assured her it was safe.

[mbamber]

Have an earth wire connected to a Metal Pipe going to ground or any metalwork going to the ground.  If not ram a steel rod zinc coated if possible into the Ground and attach a cable to it.

[Crossy]

Finding a ground in an older property is always an issue.

 

1. If you don't already have one an RCD/RCBO is essential. You can get a small unit for 500 Baht or so to just serve the shower or whole house Safe-T-Cut units for about 5k Baht. If you're not sure what you have look for a "Test" button, this is the easiest way to identify an RCD/RCBO, still not sure, post a photo.

 

2. An older building my well have metal water supply pipes. Clamping your ground onto one of these is a good option but don't use a fire pipe.

 

3. If you can get to the ceiling space there may well be exposed building steel which you can use.

 

4. There may actually already be a ground in the breaker box which just hasn't been distributed.

 

[oldcarguy]

I assume  RCD/RCBO units are sized to what you have hooked up to it  , 

so how do you pick which one to buy  ?

 

Thanks for the info

[Crossy]

58 minutes ago, oldcarguy said:

I assume  RCD/RCBO units are sized to what you have hooked up to it  , 

so how do you pick which one to buy  ?

Yes, if you're using one of the individual units to protect, say, a shower then size it as appropriate to the load. For a 3.5kW shower a 20A / 30mA (or even 10mA) would be appropriate.

 

Ensure you are getting an RCBO by checking for the "Test" button, no button, not an RCBO. 

[tutsiwarrior]

from my observations looks like the shower's integral ELCB unit won't work unless there is a ground...if no ELCB operation (ie, no ground) then the water heating circuit won't operate and fitter/installer must demonstrate shower hot water operation before the job is finished...believe that I'd leave it up to the installer to ensure that the ground is in place...

 

or maybe he can sneak in there with some alligator clips, etc...

 

we've got an RCBO on the supply to the CB and the shower installer also installed a 30A breaker on the supply local to the shower unit which looks to be the usual arrangement...

 

 

Edited April 10, 2018 by tutsiwarrior

[poanoi]

i know of a woman who cleverly put the earth cable into a small can of earth holding a flower

Edited April 11, 2018 by poanoi

[Crossy]

15 hours ago, tutsiwarrior said:

from my observations looks like the shower's integral ELCB unit won't work unless there is a ground...if no ELCB operation (ie, no ground) then the water heating circuit won't operate and fitter/installer must demonstrate shower hot water operation before the job is finished...believe that I'd leave it up to the installer to ensure that the ground is in place...

Most RCD/RCBO's don't need a functional ground (those that do won't stay on without the ground). I know our two big water heaters have the no ground needed type, the new shower heater actually has an extra wire on the incoming ground terminal so I assume it needs a functional ground.