cheers
RCD tripping with mains saw
Nov 18, 2016
43 Replies
I knew someone would know the correct terminology.
A B20 (which would ok with 2.5mm^2 T&E in most cases), will allow 100A of inrush current. A C16 will allow 160A of inrush.
(your current B16 allows 80A)
What kind of motor is in the saw - is it a loud universal brushed motor, or a quite induction motor?
Remove the RCD, they're a bloody nuisance as you've found out.
Fuses don't nuisance trip. Get rid of the newfangled s*it.
I think the whole point is that they are not supposed to work!
Chopping through the cable with the sharp end of a tool tends to make the presence of an RCD desirable.
Whether it's a 30mA RCD or 300mA RCD that is required can be determined using DNA profiling.
Quite a few users of uk.d-i-y would be fine with a 300mA unit :-)
AB
A 16A or 20A C type type will be OK with that sort of run. No calculations are needed.
A 32A B type will also be OK and will have the added advantage that it will annoy dennis.
I thought you might like to break out the adiabatic equation, until Jack mentioned it was all within reach of the CU!
No need for all that bollocks.
However there is a chance that if the OP lives close to a substation then a short circuit may destroy the MCB. That applies to all circuits at the house.
snip
It is quite noisy 1600 Watt - so guess a universal brushed motor
That is incorrect.
A C16 MCB will have a similar fault trip threshold to a BS3036 15A fuse.
Off you go then...
Never seen a fuse blow with anything other than a short.
I've never had an MCB or other crap in my house.
MCB swapped for Type C 32 Amps - job's a good 'un Thanks to all for advice.
32A? Properly you should use 4mm^2 with that.
Could you not get a 16A or 20A type C?
Or make it a very short ring with 2.5mm^2
No-one suggested that you should fit a C type 32A MCB.
We've established upthread that the 2.5^2 is short enough.
Not short enough for a C type 32A MCB on a TN-S supply that is at the upper limits of it's maximum allowed Zs.
If its a short radial with only one double socket on it, then the MCB is only required for fault protection anyway.
As I was in the workshop this evening I thought I should check my claim about my 9" angle grinder tripping the supply. Er... the MCB is in fact a 16amp B type....
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