Question for the experienced

[Burnt Fingers]

Been PT testing last week (yawn) and have a odd one:

13A Double Socket with a 2.5mm running 10" toa 16A Comando Socket, which feeds a circuar saw. It needs to on a 16A socket or in winter, the inrush pops a 13A cartridge use. Its a ring main to the socket, protected by 20A Type B Mcb.

16A Socket is cracked so I want to replace it

I cannot find anythng in the regs but it feels wrong. Anyone wlling to give a helpful answer?
BF

 

[Guest111]

Without knowing the loading of the saw it's difficult to make a correct decision,was it put on a 13a plug originally by design or simply because that's what someone thought it should be on?

 

[Burnt Fingers]

Without knowing the loading of the saw it's difficult to make a correct decision,was it put on a 13a plug originally by design or simply because that's what someone thought it should be on?

It was on a 16A when I got there. Reason for question is socket is cracked. At some point in history it was on a 13A plug but was changed due to staff bypassing fuse. Flex is 4mm, no voltsstop switch rated at 40A.

Startright Tilt Arbor, only ever seen them fixed wired or on IEC 60309.

 

[Guest111]

It was on a 16A when I got there. Reason for question is socket is cracked. At some point in history it was on a 13A plug but was changed due to staff bypassing fuse. Flex is 4mm, no voltsstop switch rated at 40A.

Startright Tilt Arbor, only ever seen them fixed wired or on IEC 60309.

well in that case if it were me then the 16A socket would be being protected by a 16A mcb.

 

[Burnt Fingers]

Looked up my info - its a 2.2Kw Motor for 3ph but converted to single. Clamped, it draws 38A at startup and runs free at 6.8A, cutting at 10.8A

 

[Burnt Fingers]

well in that case if it were me then the 16A socket would be being protected by a 16A mcb.

Yea - I can put an MCB in for the socket easy enough.

 

[rapparee]

Does the rest of thr ring carry much of a load. Would a 16a mcb be forever tripping

 

[Burnt Fingers]

They use woodworking machines - a fair load but only one machine at once, so no not really. If it trips now and again then its less of a problem than a bridged 13A fuse I guess!

 

[ipf]

Is it a ring? Have you tested to check? .... ring isn't complete so a lesser cb installed?...may be 2 radials!

 

[Burnt Fingers]

Nice one - its a ring though.

 

[Leesparkykent]

how far is the saw from the 1st leg of the ring, if its close or could extend 1st leg of the ring to the saw and put 16amp socket on the end of this and put this leg on a 16 amp mcb then leave the the rest on the 20amp mcb and disconnect leg inbetween leaving you with two radials with one dedicated to the 16amp socket.

 

[rapparee]

By all means tell me i'm wrong but why should you derate the circuit further to 16a just because there is a commando socket present. Id be more inclined to put in a 32a commando socket/plug and leave the 20a MCB or even replace with 32a MCB if conditions allow.

 

[Burnt Fingers]

16A is what was in, but you are right, circuit rating is 20A so yea

 

[davesparks]

extend on leg of the ring fron socket and add the commando to the ring. sockets are rated at 20amps anyway so its fine

16A sockets are rated to 16A, not 20A, otherwise they would be called 20A sockets.


However a circuit supplying 16A sockets is permitted to be protected at 20A.

 

[Leesparkykent]

I take it the ring is wired in 2.5 so if what I said was done both radials could either be put on a 20amp or 16amp mcb. any thing rated over 2kw should really be put on its own dedicated circuit. that my view on it any way.

 

[Engineer54]

It was on a 16A when I got there. Reason for question is socket is cracked. At some point in history it was on a 13A plug but was changed due to staff bypassing fuse. Flex is 4mm, no voltsstop switch rated at 40A.

Startright Tilt Arbor, only ever seen them fixed wired or on IEC 60309.

I doubt very much that this machine was ever on a 13A plug top, if it was, i'd of loved to have seen the 4mm cord terminations into the 13 A plug top!! lol!!

BTW the 13A fuse is there to protect the flex/cord, NOT the machine/appliance etc.