Problem I have 9.5 Kw shower on a 6mm t&e wired through a 45a plug in mcb in a old one way wylex, cable is tested ok but circuit breaker getting very hot when shower is on, no insulation cable capacity 47 amps, connections good and tight, puzzled to the problem
OVERHEATING CABLE
- Thread starter notyou
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i too have a 9,5kW shower on a 6mm2 cable and after a decent long shower, say 15 minutes, the cable temperature will rise slightly above ambient. No way would I say it was warm, let alone hot.
Plug-in as in a replacement for rewireable cartridge?
If so, in what condition are the contacts into which the MCB module plugs? If they're old and tired then the connection may not be as good as you think it is.
Also, have you confirmed that this MCB is supplying only the shower?
Also, what is the CCC of the way in the CU?
You could overcome all possible problems by adding a separate CU for the shower, and add the benefit of an RCD for that circuit (if you don't already have one).
If so, in what condition are the contacts into which the MCB module plugs? If they're old and tired then the connection may not be as good as you think it is.
Also, have you confirmed that this MCB is supplying only the shower?
Also, what is the CCC of the way in the CU?
You could overcome all possible problems by adding a separate CU for the shower, and add the benefit of an RCD for that circuit (if you don't already have one).
Notyou, have a look on the front of your fuseboard.
Does it have a label saying 'maximum load 60A'??
That might give you a clue why its getting hot. It may just be a loose connection in the board but be aware that those boards are not designed for the load you are now giving them.
Just work it out
Shower
Cooker?
Ring final
Thats way over the top.
Both of you boys are lucky not to have melting cables. you need 10mm cable for 9.5KW shower.
Does it have a label saying 'maximum load 60A'??
That might give you a clue why its getting hot. It may just be a loose connection in the board but be aware that those boards are not designed for the load you are now giving them.
Just work it out
Shower
Cooker?
Ring final
Thats way over the top.
Both of you boys are lucky not to have melting cables. you need 10mm cable for 9.5KW shower.
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thanks for the advice,
In more detal
the one way fuse board wylex originally had a 30 rewireable fuse and melted the original but old 6mm cable (imperial equivalent)on the 9.5 kw shower.(40 amp load)
The cable only needs to be 6mm it carries 47amps look in your regs.
the cable is brand new.
The one way board is only suppling the shower via a 10mm tail from the meter. there is a seperate fuseboard for rest of house
All insulation ZE continuity is perfect but the plug in replacement 45A mcb thats replacing the 3036 is getting really hot and it tripped out.
Anyone know what a old wylex one way is rated at I thought it could switch 45amps? or do they have a problem after time with a 40 amp load?
any further views will be greatley appreciated as its totally flumexed me
In more detal
the one way fuse board wylex originally had a 30 rewireable fuse and melted the original but old 6mm cable (imperial equivalent)on the 9.5 kw shower.(40 amp load)
The cable only needs to be 6mm it carries 47amps look in your regs.
the cable is brand new.
The one way board is only suppling the shower via a 10mm tail from the meter. there is a seperate fuseboard for rest of house
All insulation ZE continuity is perfect but the plug in replacement 45A mcb thats replacing the 3036 is getting really hot and it tripped out.
Anyone know what a old wylex one way is rated at I thought it could switch 45amps? or do they have a problem after time with a 40 amp load?
any further views will be greatley appreciated as its totally flumexed me
Or 46.0A for sheathed cable, and only if uninsulated along the entire length.notyou said:
Are there any other facts that you haven't reported yet?
Was the MCB brand new?
Are you absolutely sure that the shower rating is 9.5kW?
Have you used a clamp meter to check the load?
oh and there is a big label on the inside of shower that says 9500 watts load 39.5 amps 240
37 ish at 230v
Shower has not been in use for a year and there was signs of the old cable melting at the switch, even a new pull switch 45a has been installed.
Could a lime scale buildup make it draw too much power??
37 ish at 230v
Shower has not been in use for a year and there was signs of the old cable melting at the switch, even a new pull switch 45a has been installed.
Could a lime scale buildup make it draw too much power??
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Not if it is a sub 100A board.
Well, you probably know this already, but if you don't have a way of measuring the load, then I can't see how you're going to find the fault, other than by guessing and replacing things until it goes away.
For example, is it in any way possible that the shower has been fitted with a 10.5kW can? Did you buy the shower? Was it in the house already? Has anyone ever 'mended' it?
For example, is it in any way possible that the shower has been fitted with a 10.5kW can? Did you buy the shower? Was it in the house already? Has anyone ever 'mended' it?
Those old Wylexes are not usualy intended to take more than 30A per way. Can you put up a pic?
What does it say next to the main switch (Load not to exceed....)?
The will also overheat if any of the connections are less than tight. Copper that has overheated once is softened and will not stay tight again.
What does it say next to the main switch (Load not to exceed....)?
The will also overheat if any of the connections are less than tight. Copper that has overheated once is softened and will not stay tight again.
there is no markings on the main switch it is that old nor on the inside of it there is a 240v reference on the inside and the number 30 moulded into the plastic in tiny letters but not 30A, i looked at the latest wylex rewirable one ways and they are rated to 45amp.
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