H
holmslaw
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2 electric showers
- Thread starter 17thman
- Start date
With a pulley system for the more intricate of staircases!!
I've got it, fit two showers but just give them one shower head!
I bet your that spark that does'nt believe in two way switchiing on staircases, he fits a pull cord switch at the top with the cord long enough to reach the ground floor.
now if it was a 45A 2 way pullcord...
the only way I can see of doing this is a second service, then you've got phaseing issues, unless the bottom flat is/can easily be a seperate electrical system. dam the electric board and their stubborn refusal to let us have 120/150 amp single phase supplies
Had to 3 phase on a house refurb a while ago, cos the mad woman wanted underfloor heating in every room (5 bed house), about 20kW in total.
And if you make the landing light a 500W MH you don't need one in the hall either, so that's another switch saved!
On the occasion of both being switched at the same time, would the controlling 50MCB on the main board trip or would the contactors burn out first and/or the 50A not trip at all.
Is the consensus then that this ingenious solution is not sufficiently safe?
Is the consensus then that this ingenious solution is not sufficiently safe?
What will happen is that both will energise the contactors, which will start to close the shower contacts and open the auxiliary ones.
The latter action will interrupt the supplies to the contactor coils, so they will fall back to the normal position and the auxiliary contacts will close.
That will energise both contactors, which will start to close the shower contacts and open the auxiliary ones.
The latter action will interrupt the supplies to the contactor coils, so they will fall back to the normal position and the auxiliary contacts will close.
That will energise both contactors, which will start....
Oh well - you get the picture.
One might be slower than the other by enough for this not to happen, but I wouldn't design a solution assuming that that will be the case
The latter action will interrupt the supplies to the contactor coils, so they will fall back to the normal position and the auxiliary contacts will close.
That will energise both contactors, which will start to close the shower contacts and open the auxiliary ones.
The latter action will interrupt the supplies to the contactor coils, so they will fall back to the normal position and the auxiliary contacts will close.
That will energise both contactors, which will start....
Oh well - you get the picture.
One might be slower than the other by enough for this not to happen, but I wouldn't design a solution assuming that that will be the case
Why would this trip the cutout ? Even a 60A cutout would not trip with the 2 showers in use, the cooker plus much more. In fact it would take over 100A for the best part of an hour to blow a 60A 1361 . Also if the showers are thermostatic, then you would find a clamp reading of significantly less than 78A.
The issue is not with the cut out, but the rating of the main switch/CU of say 100A. If you feel this is necessary, then install an additional CU and spread the loads across them.
I think I'll be best to stick with the changeover switch for my situation
http://www.tlc-direct.co.uk/Products/KMT5B37I.html
It's a bit industrial looking but will be in a cupboard.
It is simple and without risk of catastrophe. I shall put it outside the bathroom with a direct line of sight to a 45A switched neon isolating the autoclave so as not to turn it over when the autoclave is running. We'll just need to be disciplined in switching off the main switch when the autoclave is finished which is good practice anyway.
Don't know whether that would solve the OP's problem tho'
Thanks to everyone - most educational and interesting
http://www.tlc-direct.co.uk/Products/KMT5B37I.html
It's a bit industrial looking but will be in a cupboard.
It is simple and without risk of catastrophe. I shall put it outside the bathroom with a direct line of sight to a 45A switched neon isolating the autoclave so as not to turn it over when the autoclave is running. We'll just need to be disciplined in switching off the main switch when the autoclave is finished which is good practice anyway.
Don't know whether that would solve the OP's problem tho'
Thanks to everyone - most educational and interesting
wow... thanks for the input, love the burning house BAS. I am the op. manual changeover for me or the client goes for a power shower
78 amps for showers, no diversity allowed, plus, with diversity, say 20A for hob and oven. Immersion 12A, kettle, toaster, hair drier, wash mach, rest of the stuff and the discharge lamps spotting santa with all the family around and the tails split like eqiutum says. cut out will go.
Thanks steve, still like it but bloody expensive.
lol
78 amps for showers, no diversity allowed, plus, with diversity, say 20A for hob and oven. Immersion 12A, kettle, toaster, hair drier, wash mach, rest of the stuff and the discharge lamps spotting santa with all the family around and the tails split like eqiutum says. cut out will go.
Thanks steve, still like it but bloody expensive.
lol
17thman, you appear to be under the impression that electric appliances with heating elements are constantlydrawing full load when in use and that families exist who switch everything on and then have a shower for an hour (or two showers in this case). This is not the case, and cutout fuses, from my experience, and in general, go don't go pop unless under fault conditions.
Regardless of how may showers are in an installation one could easily paint a worst case scenario where every possible load is switched on at the same time. This is why diversity exists.I know diversity does not apply to 2 showers but even so, is not a major issue, especially fed from two CU's.
Someone will soon post the old classic of christmas day,with all the family round, cookers and hobs going etc and the cutout goes....it doesn't happen !
Furthermore, assuming that the two showers are fed from normal mains water pressure, they would find that the flow would be to small with both in operation for either to be able to enjoy a decent shower, so they would simply wait the few minutes until the other finishes !
Regardless of how may showers are in an installation one could easily paint a worst case scenario where every possible load is switched on at the same time. This is why diversity exists.I know diversity does not apply to 2 showers but even so, is not a major issue, especially fed from two CU's.
Someone will soon post the old classic of christmas day,with all the family round, cookers and hobs going etc and the cutout goes....it doesn't happen !
Furthermore, assuming that the two showers are fed from normal mains water pressure, they would find that the flow would be to small with both in operation for either to be able to enjoy a decent shower, so they would simply wait the few minutes until the other finishes !
while such oscilation could in principle happen it strikes me as pretty unlikely.
Unlikely enough so that if you'd come up with Steve's design you'd guarantee that you'd taken all reasonable precautions to prevent it?
You're using a PC to write messages on a forum website - you don't need to use SMS-style abbreviations.
As for the explanation, the whole point of diagrams is to explain things with a great deal more clarity and less chance of misinterpretation or vagueness than a written explanation involves. What is it that you can't understand when you look at it?
Have you tried printing out two copies and using a highlighter to show which current paths are active when the LH switch is on and which when the RH one is on? The whole point of the design is to safely cope with both switches being on at the same time, and to try to describe in words what happens with each of the 4 possible combinations of switch activations (assuming a genuinely simultaneous one is impossible) would, I'm sure, end up more confusing than the diagram.....
As for the explanation, the whole point of diagrams is to explain things with a great deal more clarity and less chance of misinterpretation or vagueness than a written explanation involves. What is it that you can't understand when you look at it?
Have you tried printing out two copies and using a highlighter to show which current paths are active when the LH switch is on and which when the RH one is on? The whole point of the design is to safely cope with both switches being on at the same time, and to try to describe in words what happens with each of the 4 possible combinations of switch activations (assuming a genuinely simultaneous one is impossible) would, I'm sure, end up more confusing than the diagram.....
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