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

  • State Helpful Answer
  • Locked Locked
  • Replies 16 replies
  • Subscribers 32 subscribers
  • Views 1500 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

Two Faults.

Zoomup

I went to explore the reason for a failed immersion heater. The element tested out o.k. The rod 'stat had its main operating contacts welded together and the safety trip had operated and switched the element off. I renewed the rod 'stat. Then upon turning on the 20 Amp D.P. switch with neon it flickered the neon momentarily then it died. There was a supply in from a good old 60s M.K. 20 Amp switch down stairs, still operating perfectly, but its neon is a little dim. But the newish 20 Amp D.P. switch by the immersion heater had failed after about 2 years use from new. So I found one fault, and by operating the switch by the heater that switch then failed. You couldn't make it up, and then trying to explain that to the customer isn't easy.

Has anybody else had similar experiences?

Z.

Parents
  • 0

    The airing clothing and bedding will protect the wall mounted switch from the heat of the tank and pipes. It will act like a thermal insulator.

    But also restricting the heat that can be lost from the switch - like a cable in a thermally insulated wall.

    Also thermal insulation isn't quite like electrical insulation in that with electrical insulation we tend to think of it as a practically perfect insulation - once you've got a thin layer of electrical insulation the amount of 'leakage' is negligible so we can ignore it - but thermal insulation is much more of a 'semiconductor' - it may half or quarter (or whatever) the amount of heat leakage, but never entirely eliminates it. The net upshot of which is that you get a temperature gradient across thermal insulation - not just deliberate insulation but all materials - so the switch will have an ambient temperate somewhere between that of the tank and that of the outside, depending on the ratio of thermal insulation on each side of the 'sandwich' it finds itself in.

       - Andy.

Reply
  • 0

    The airing clothing and bedding will protect the wall mounted switch from the heat of the tank and pipes. It will act like a thermal insulator.

    But also restricting the heat that can be lost from the switch - like a cable in a thermally insulated wall.

    Also thermal insulation isn't quite like electrical insulation in that with electrical insulation we tend to think of it as a practically perfect insulation - once you've got a thin layer of electrical insulation the amount of 'leakage' is negligible so we can ignore it - but thermal insulation is much more of a 'semiconductor' - it may half or quarter (or whatever) the amount of heat leakage, but never entirely eliminates it. The net upshot of which is that you get a temperature gradient across thermal insulation - not just deliberate insulation but all materials - so the switch will have an ambient temperate somewhere between that of the tank and that of the outside, depending on the ratio of thermal insulation on each side of the 'sandwich' it finds itself in.

       - Andy.

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