mcbs

phiggis · 20 May 2005

hi, i have just installed a 10.5kw rated shower, which replaced an old 7.5kw, the problem is the old 32amp fuse is not powerfull enough for this shower and i cannot seem to find one any where, its a type2 nsb,
ive been told that they are an old type fuse and are hard to get hold of , am i right? plus the shower recomends a 45amp and i have read they dont make them any more, i am a novice when i comes to electrics, can someone help! thanx phil.

andy · 20 May 2005

phiggis said:
hi, i have just installed a 10.5kw rated shower, which replaced an old 7.5kw, the problem is the old 32amp fuse is not powerfull enough for this shower and i cannot seem to find one any where, its a type2 nsb,
ive been told that they are an old type fuse and are hard to get hold of , am i right? plus the shower recomends a 45amp and i have read they dont make them any more, i am a novice when i comes to electrics, can someone help! thanx phil.

what size is the cable to the shower? it needs to be 10mm. and what is the length of the run?

do you have an RCD protecting the shower?>

ban-all-sheds · 20 May 2005

Oh dear.

andrew2022 said:
what size is the cable to the shower? it needs to be 10mm

I reckon there's zero chance of that.

I also reckon there is a small but non-zero chance that it might only be 4mm².....

securespark · 20 May 2005

Ban

Perchance the chance of the cable being 4mm is slightly greater than the chance of it being 10mm??

ban-all-sheds · 21 May 2005

Probabibly...

Anyway - levity aside - phiggis - you must not simply upgrade the fuse to 45A - this could be very dangerous.

delmel · 21 May 2005

phiggis said:
hi, i have just installed a 10.5kw rated shower, which replaced an old 7.5kw, the problem is the old 32amp fuse is not powerfull enough for this shower and i cannot seem to find one any where, its a type2 nsb,
ive been told that they are an old type fuse and are hard to get hold of , am i right? plus the shower recomends a 45amp and i have read they dont make them any more, i am a novice when i comes to electrics, can someone help! thanx phil.

Type2 nsb is acually an MCB made by wylex type 2 and the catalogue reference is NSB follwed by the amps NSB32 = 32amp. It is and i am sure you may still be able to get in both 40 and 50 amps (you will need the 50) Be very careful though you also should check your cable size to ensure that is correct 10mm is what i would like to see.
TLC should have in stock

www.tlc-direct.co.uk

ban-all-sheds · 21 May 2005

Phiggis - 10mm² is essential if you're going to use a 50A breaker.

See this: //www.diynot.com/forums/viewtopic.php?p=81696#81696

phiggis · 21 May 2005

hi, i was concerned about upgrading an ncb in my consumer unit from a 32 amp to a 45amp, the cable i am sure is 6mm2 and is less than 1.5 metres from the unit to the shower, it is protected by a 30 amp rcd on the unit ,is this ok if i just upgrade the fuse?.. thanx for the replies and i hope this is a little clearer than before..

andy · 21 May 2005

phiggis said:
hi, i was concerned about upgrading an ncb in my consumer unit from a 32 amp to a 45amp, the cable i am sure is 6mm2 and is less than 1.5 metres from the unit to the shower, it is protected by a 30 amp rcd on the unit ,is this ok if i just upgrade the fuse?.. thanx for the replies and i hope this is a little clearer than before..

if your RCD is 30A then there is something wrong. and you need to be 100% certain of what size cable it actually is

ban-all-sheds · 21 May 2005

phiggis · 22 May 2005

andrew2022 said:
phiggis said:

hi, i was concerned about upgrading an ncb in my consumer unit from a 32 amp to a 45amp, the cable i am sure is 6mm2 and is less than 1.5 metres from the unit to the shower, it is protected by a 30 amp rcd on the unit ,is this ok if i just upgrade the fuse?.. thanx for the replies and i hope this is a little clearer than before..

Click to expand...

if your RCD is 30A then there is something wrong. and you need to be 100% certain of what size cable it actually is

sorry i forgot to add the m, it is a 30 mA RCD but do i still need to upgrade to 10mm2 cable or will 6mm2 cope with the load, if i change to a 45 or 50 amp mcb? thanx phil...

andy · 22 May 2005

phiggis said:
andrew2022 said:

phiggis said:

hi, i was concerned about upgrading an ncb in my consumer unit from a 32 amp to a 45amp, the cable i am sure is 6mm2 and is less than 1.5 metres from the unit to the shower, it is protected by a 30 amp rcd on the unit ,is this ok if i just upgrade the fuse?.. thanx for the replies and i hope this is a little clearer than before..

Click to expand...

if your RCD is 30A then there is something wrong. and you need to be 100% certain of what size cable it actually is

Click to expand...

sorry i forgot to add the m, it is a 30 mA RCD but do i still need to upgrade to 10mm2 cable or will 6mm2 cope with the load, if i change to a 45 or 50 amp mcb? thanx phil...

change to 10mm^2. the RCD protects again earth leakage, NOT overload. thats what the MCB is for. but your gonna change it for a larger type which the cable might not support. the RCD is there for your own safety

phiggis · 24 May 2005

andrew2022 said:
phiggis said:

andrew2022 said:

phiggis said:

hi, i was concerned about upgrading an ncb in my consumer unit from a 32 amp to a 45amp, the cable i am sure is 6mm2 and is less than 1.5 metres from the unit to the shower, it is protected by a 30 amp rcd on the unit ,is this ok if i just upgrade the fuse?.. thanx for the replies and i hope this is a little clearer than before..

Click to expand...

if your RCD is 30A then there is something wrong. and you need to be 100% certain of what size cable it actually is

Click to expand...

sorry i forgot to add the m, it is a 30 mA RCD but do i still need to upgrade to 10mm2 cable or will 6mm2 cope with the load, if i change to a 45 or 50 amp mcb? thanx phil...

Click to expand...

change to 10mm^2. the RCD protects again earth leakage, NOT overload. thats what the MCB is for. but your gonna change it for a larger type which the cable might not support. the RCD is there for your own safety

thanx for the advise, and have finnally decided to get it sorted by some one who nows what they are doing, plus im also having the lot rewired to be on the safe side, aint taking now chances anymore..
thanx for everyones advice. phil.

ban-all-sheds · 24 May 2005

So on the basis of your original question, if you had been able to easily find a 45A MCB, e.g. in one of the sheds, you'd have stuck it in with nary a thought....

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