Electrode Boiler

[ianphilip007]

just trying to understand this regulation as to why the shell needs to be bonded to the neutral as well as earthing conductor for a electrode water heater

(554.17 where the the supply to am electrode water heater or electrode boiler is single phase and one electrode is connected to a neutral conductor earthed by the distributor, the shell of the electrode water heater or boiler shall be connected to the neutral of the supply as well as to the earthing conductor).

 

[oldtimer]

Make
Model
picture
Location (domestic or commercial)
As looking glass no worky worky

 

[ianphilip007]

wouldnt this cause the nuetral and earth to be effectively a pen conductor by that i mean the nutral and earth now performing the same function (not the same cable)

though i might be mistaken

 

[ianphilip007]

hi old timer no perticular model just trying to understand the reg 554.17 which states that the casing of boiler should be bonded to the nutral supply as well as the earth.

 

[ianphilip007]

C - Single-phase electrode heaters {Fig 7.15}

Fig 7.15 - Single-phase electrode heater

 

[ianphilip007]

im assuming that these electrode boilers would not be used in a domestic enviroment as i thought neutral /earthing conductors had to be seperate within a domestic installation.

 

[ianphilip007]

any thoughts ??

 

[ianphilip007]

can anyone explain why the casing must be bonded to the nuetral as well as earth ??

 

[johnboy6083]

Because it is the return path of the current that flows through the water. In effect the element is an anode, and the shell of the heater is the cathode. I'm guessing that they want it connecting to earth also, in order to provide a clean path for fault current, in order for the protective device to operate. I also agrees with one of your earlier posts, that an RCD could not be used with this type of equipment.