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 9878 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.
  • 0
    Customers never cease to be amazed at how big some of the holes became in their immersion heaters before finally packing up, often without taking a fuse or MCB out.
  • 0
    I presume they no longer heated the water though, probably because the element failed due to overheating in a steam bubble?
  • 0
    I've seen an immersion fail and  melt the wiring supplying it, where it changed from 3kW to about half the expected resistance, to earth, so had there been an RCD it would have tripped, but this was in the dark ages when an RCD was not called that and I had not yet used one in earnest.

    The hot wire 15A fuse didn't melt but the PVC on the wires did.

    Just the one mind, in the mid 1980s.

    Looked undamaged when it came out, so maybe a manufacturing defect.

    Mike

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