AJJewsbury:

What does this control panel do? If there are any electronics in there then that might have an implication for RCDs - especially if it might try to regulate things by chopping the AC waveform to the heaters.


Will all the elements be on the same item of equipment? (I'm just wondering if it makes more sense to mount the control panel along with the heaters on the (movable) equipment and then have a single lead to a wall socket (which would presumably then be rather a large one >>32A and so perhaps not be subject to the 30mA RCD requirement).


What do the control panel manufacturer's installation instructions say?


If there are unknowns my gut feeling would be for a single RCD upstream of the controller, with some means to isolate individual elements so that if one goes faulty it can be isolated and the RCD reset to allow the others to continue to to work - but as before there are lots of factors many of which I can't see from here so don't take that as a recommendation.


   - Andy.

Cheers Andy. 


To clarify the Control Panel has 6 Three-phase circuits.  Each circuit has Rail Mounted Cartridge Fuses, Contactors, On/Off Rotary Switches and Pilot Lights.  At present I will only be using 4 of these circuits to switch each of the immersion elements when required.  2 of the 4 circuits being used will be switched via PID for temperature control.  It does not have any RCD protection.


2 elements on one vessel, 2 elements on another.  Vessels are about 3m apart.  Interesting idea though.


Don't have any Control Panel instructions.


When you say "upstream", do you mean before the Control Panel?  Wondering if a direct feed from a Distribution Board RCD to the Control Panel could be an option for universal protection at less cost?  Is this possible and allowed?  Alternatively, tails split with a Henley Box >>> RCD >>> Control Panel?

AJJewsbury:

What does this control panel do? If there are any electronics in there then that might have an implication for RCDs - especially if it might try to regulate things by chopping the AC waveform to the heaters.


Will all the elements be on the same item of equipment? (I'm just wondering if it makes more sense to mount the control panel along with the heaters on the (movable) equipment and then have a single lead to a wall socket (which would presumably then be rather a large one >>32A and so perhaps not be subject to the 30mA RCD requirement).


What do the control panel manufacturer's installation instructions say?


If there are unknowns my gut feeling would be for a single RCD upstream of the controller, with some means to isolate individual elements so that if one goes faulty it can be isolated and the RCD reset to allow the others to continue to to work - but as before there are lots of factors many of which I can't see from here so don't take that as a recommendation.


   - Andy.

Cheers Andy. 


To clarify the Control Panel has 6 Three-phase circuits.  Each circuit has Rail Mounted Cartridge Fuses, Contactors, On/Off Rotary Switches and Pilot Lights.  At present I will only be using 4 of these circuits to switch each of the immersion elements when required.  2 of the 4 circuits being used will be switched via PID for temperature control.  It does not have any RCD protection.


2 elements on one vessel, 2 elements on another.  Vessels are about 3m apart.  Interesting idea though.


Don't have any Control Panel instructions.


When you say "upstream", do you mean before the Control Panel?  Wondering if a direct feed from a Distribution Board RCD to the Control Panel could be an option for universal protection at less cost?  Is this possible and allowed?  Alternatively, tails split with a Henley Box >>> RCD >>> Control Panel?