Firstly, which requirement for RCDs are you attempting to satisfy? (in many situations on a TN system they'd likely not be required at all). Are there any upstream RCDs that you'd need to discriminate with (which might suggest against solid N RCBOs for instance).
Then what are the operational requirements? Is it acceptable to the user to have all the immersions disconnected if one developed a fault? (if they're all part of the same process that might actually be perfectly acceptable or even desirable, in other situations keeping the others running at all costs might be top of the list).
I would need the other 3 Immersions to remain connected if 1 develops a fault.
As I understand it SPNetworks have installed a TNS System. They have connected via the sub-station down the road. I have a Earth Terminal Block to connect to - Do this sound right?
I would need the other 3 Immersions to remain connected if 1 develops a fault.
Are there any earth leakage (protective conductor) currents to take into account? Mineral insulated elements have a bit of a reputation for being a little leaky, and you have quite an amount of them there. On the other hand spread over three phases the leakage should tend to cancel out .... unless there's any option to switch each phase individually (for reduced output for instance).
Not sure what Protective Conductor means?
No option to switch each phase, just able to switch individual elements on/off depending on output required, i.e 9kW or 15kW (9kW & 6kW).
These are the elements I'm looking to install: https://processheatingservices.com/immersion-heaters/screwed-immersion-heaters/industrial-heaters-piirange/
Cheers, Dan.
If you're using the supplier's earthing facility it'll certainly be TN. (I'd be surprised if it was really TN-S these days (unless it was an odd situation like a caravan site or a marina) - most DNOs seem pretty wedded to TN-C-S these days, even combining N and PE in modification to what were originally TN-S networks, effectively making them TN-C-S even though they appear for all the world to be TN-S at the cut-out.)
Cheers Andy. Spot on! I've just double checked the SPNetwork invoice and it is 40kVA TN-C-S. It's for a Nano/Micro Brewery. I'm hoping to do a fair amount of the install myself and get a qualified sparky to connect tails, check and test before operation.
I would need the other 3 Immersions to remain connected if 1 develops a fault.
Then no common RCD then - which leaves you with a choice of individual RCD (RCCBs or RCBOs) for each circuit, or no RCDs at all - so back to the 1st question on that.
The Control Board is already built, came with the rest of the gear. It has Rail Mounted Cartridge Fuse Holders. I think the most economical solution would be to fit downstream Isolators with RCDs? Would you agree? Thinking I would like RCDs for the extra safety? Cheers, Dan.
Not sure what Protective Conductor means?
I'm hoping to do a fair amount of the install myself and get a qualified sparky to connect tails, check and test before operation.
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