Guys, the wire in my 9.5kW shower melted. I measured it at 6mm2. I'm replacing the shower using a 10mm2 cable. The shower is only connected to a mcb in the CU. How do I incorporate an RCD?
Adding and RCD
- Thread starter xAlex
- Start date
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What type of consumer unit have you got ? you may be able to get a rcbo to replace the existing mcb.
Or
Take cable from mcb into a 30mA rcd in an enclosure sited next to the cu, then take cable from cu upto the shower switch.
Or
Take cable from mcb into a 30mA rcd in an enclosure sited next to the cu, then take cable from cu upto the shower switch.
What size is the mCB in your consumer unit?
As you will need to replace the MCB you could buy an RCBO to go in that position.
Dont forget you are providing a new circuit into a bathroom so you have to take the usual steps re notification, bonding etc.......
edit: Damn you, comms!!!!!!
As you will need to replace the MCB you could buy an RCBO to go in that position.
Dont forget you are providing a new circuit into a bathroom so you have to take the usual steps re notification, bonding etc.......
edit: Damn you, comms!!!!!!
But before you do that you need to find out why the cable melted. Was there a fault with the shower? Is the cable run through insulation? Has the isolator been damaged? Has the shower been damaged? Are you sure 10mm² is sufficient or have you just thought 'I'll go up one size, that'll do'?
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http://m1.freeshare.us/view/?155fs347827.jpg
I have put a photo of the CU at this address. Th phase conductor melted in the shower casing. I assume it was due to the fact that the shower was a 9.5kW with a 6mm cable. It did run through a couple of meters of insulation. So, an RCBO could directly replace the mcb do you think?
Cheers
I have put a photo of the CU at this address. Th phase conductor melted in the shower casing. I assume it was due to the fact that the shower was a 9.5kW with a 6mm cable. It did run through a couple of meters of insulation. So, an RCBO could directly replace the mcb do you think?
Cheers
xAlex said:
If it was the end of the cable next to the connection block in the shower then a loose connection would be the most likely cause of the overheating.
Your shower is already RCD protected... Notice the label saying 'RCD protected circuits'?
Your shower is protected by a 32A MCB when a 9.5kW shower will draw about 40A @240v. Not a big deal unless it's tripping a lot, but when you replace the cable (while keeping it clear of the insulation) you might want to install a more suitable MCB (40A)
When you make the order for the cable and MCB also get a suitable blanking plate for that gap.
When you open up the CU (after isolating it correctly first..) make sure the connections to the busbar are sound. You have a mix of different MCBs and the connections may not be too rosey.
Your shower is protected by a 32A MCB when a 9.5kW shower will draw about 40A @240v. Not a big deal unless it's tripping a lot, but when you replace the cable (while keeping it clear of the insulation) you might want to install a more suitable MCB (40A)
When you make the order for the cable and MCB also get a suitable blanking plate for that gap.
When you open up the CU (after isolating it correctly first..) make sure the connections to the busbar are sound. You have a mix of different MCBs and the connections may not be too rosey.
Will that 63A VOLEX RCD be man enough??,
theres cooker, 40A shower, some rings.
Cant see where the RCD circuits stop. I'm assuming the three 6s & the 16 are on the non rcd side..
theres cooker, 40A shower, some rings.
Cant see where the RCD circuits stop. I'm assuming the three 6s & the 16 are on the non rcd side..
TTC, I think the 3 MCB's to the right are RCD protected - at least that is what the label implies due to the thicker black line. Although I'm not sure I would trust them, it looks a bit of a shambles.
Alex, could you remove the cover of the CU and take a picture of the guts? Be very careful not to touch any of the internal parts, and it will be safer if you open the main switch (far left) but even after you do that the 2 cables entering the CU that go to the switch will still be live, so be careful not to touch them.
Alex, could you remove the cover of the CU and take a picture of the guts? Be very careful not to touch any of the internal parts, and it will be safer if you open the main switch (far left) but even after you do that the 2 cables entering the CU that go to the switch will still be live, so be careful not to touch them.
Thats why i asked, the whole thing has been added to and badly jigged around.
So, like usual, assume nothing otherwise assume will make an ASS out of U and ME.
Ahh, new daily prayer....
So, like usual, assume nothing otherwise assume will make an ASS out of U and ME.
Ahh, new daily prayer....
K
kai
Why have you got a mish mash of breakers in that CU?, I see a Wylex one, a GE one, in addition to the official Volex ones!
It looks like a bodged job to me...
It looks like a bodged job to me...
i make it 4 davey..
shower, cooker, and 2 lots of sockets..
shower, cooker, and 2 lots of sockets..
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Hmm. A 9.5kW on a 32A breaker? And I share the concerns of those others about the 63A RCD. Need an 80A RCD....
http://m1.freeshare.us/view/?155fs389578.jpg
I've appended a picture of the guts (see link). You are right, it does look like a bodge job. The cooker doesn't actually use the 32A mcb as it is a gas cooker and just plugs in. Would all these mcb's be RCD protected through the VR 63 on the right in the picture?
I've appended a picture of the guts (see link). You are right, it does look like a bodge job. The cooker doesn't actually use the 32A mcb as it is a gas cooker and just plugs in. Would all these mcb's be RCD protected through the VR 63 on the right in the picture?
i see copper between all of the breakers on the right hand side, and a distinct lack of it between them and those on the left..
this tells me that all the breakers on the right are on the rcd and the 2 on the left are on the non rcd...
you should look at getting the rcd changed to at least an 80A..
that is the max current it is designed to take, but it is not an overcurrent device and will supply more than that and never trip..
doing so may well damage the guts of the rcd to the point where it stops working or may even ( in extreme circumstances ) melt!!..
this tells me that all the breakers on the right are on the rcd and the 2 on the left are on the non rcd...
you should look at getting the rcd changed to at least an 80A..
that is the max current it is designed to take, but it is not an overcurrent device and will supply more than that and never trip..
doing so may well damage the guts of the rcd to the point where it stops working or may even ( in extreme circumstances ) melt!!..
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