Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 43 replies
  • Subscribers 32 subscribers
  • Views 9840 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Twin immersion heaters

Former Community Member
Former Community Member
I am in the process of going unvented.  I have to use immersion heaters, and the new cylinder has two.  I have one feed to the existing immersion.  It is on 2.5mm2 T&E and connects to a 32A MCB on the CU.  I'm adding a DP isolating switch in the cylinder cupboard.  Will that be complaint for one of the immersion heaters?

To fully install the cylinder (ie the second immersion), I plan ask an electrician to either
(1) run an additional 2.5mm2 T&E cable back to the CU, connect it to the existing 32A immersion heater MCB at the CU. So the MCB protects two separate cables and the 2.5 T&E is within its capacities. 

Or
(2) run a new 6mm2 T&E cable back to the CU, connect to the existing MCB and in the cylinder cupboard, split the feed to two DP isolators, one for each immersion and its timer.


I'd be grateful for advice - are both approaches compliant?  Is one better than the other?  The amount of work will be similar.
Parents
  • 0
    That 2.5 mm² T&E ought to be on a 16 A or 20 A MCB, although as ebee says, with only one (3kW) immersion, the cable could not be overloaded. By the same argument, a second 2.5 mm² cable could be added to the 32 A MCB. If you take each 2.5 mm² cable to its own isolator and then connect the supply side of the two isolators, you and up with a ring final circuit.


    Alternatively, change it for a 4 mm² radial. If it is all left loafing under the floorboards, that is just fine, but if it goes through any form of insulation (thermal or acoustic) it may be necessary to go up a size to 6 mm².


    HTH.
Reply
  • 0
    That 2.5 mm² T&E ought to be on a 16 A or 20 A MCB, although as ebee says, with only one (3kW) immersion, the cable could not be overloaded. By the same argument, a second 2.5 mm² cable could be added to the 32 A MCB. If you take each 2.5 mm² cable to its own isolator and then connect the supply side of the two isolators, you and up with a ring final circuit.


    Alternatively, change it for a 4 mm² radial. If it is all left loafing under the floorboards, that is just fine, but if it goes through any form of insulation (thermal or acoustic) it may be necessary to go up a size to 6 mm².


    HTH.
Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines