crabtree flat plate 1gang 2 way switch innards - available?

[Jim K]

Had a short on a light fitting. Tripped the mcb & rcd.

Repaired fault and went to switch light on, to discover switch now "always on" and not turnable off?!?!

It now won't break elec. contact and won't latch in the "off" position, i.e . it's no longer a switch..

Its a crabtree flat plate, screwless front 1gang 2 way light switch in bras s.

The "switch" is attached to the metal backplate with one screw and a locati on tab at the other end.. presumably some sort of grid switch?

I've goggled various phrases to try and find something similar to try and j ust buy the "switch" bit as opposed to the whole bloody brass lightswitch a t £10+.

Anyone got any clues please on where to get just a spare "switch" not the w hole shooting match?

CHeers Jim K

[Dave W]

Surely you can dismantle the switch and force the welded contacts apart?

[Jim K]

Dave W

No apparent way in!

Moulded brown plastic with 3 terminals.

How come contacts welded with a 30ma rcd installed & working?

Jim K

[Fredxxx]

I think the tripped MCB might be a clue. RCDs often trip simultaneously.

[John Rumm]

The fault was an overcurrent rather than an earth fault current. So the RCD trip was probably just in response to the transient and a reflection on the fact that its probably sensitised to the point of being close to tripping due to the leakage normally present in the circuit.

So you would have had at least 30A through the switch briefly.

[harryagain]

The 30ma is the current to earth before it trips. It probably tripped as a result of a transient ie not a "real" fault to earth. The actual damage was due to the short circuit & could have been 60-100a for a few miliseconds. A lot depends on what part of the cycle is happening at the instant the fault occurs.

[Dave Liquorice]

Even when the module is removed from the plate by taking out the screw and disengaging the tab?

You may find that a cheaper plastic switch from the same maker has the same module on the back.

[ARW]

Well 30mA is (roughly) the minimum that will trip a RCD, the RCD does not limit the current to 30mA in the event of a direct short. There was probably

6000A flowing when the RCD and MCB tripped.

Anything in here to help you?

[Jim K]

nope.

yup will try that when I get some tuits.

Cheers Jim K

[Jim K]

mmm lots of minutely different variations of Platinum Flat plate yokes and switches.... none of which appear to be what I have here :>(

Cheers Jim K

[ARW]

No number on the one you have?

[Jim K]

No number on the one you have?

--Adam

Placcy switch :- BS EN 60669 1M

10AX 250V

Yoke :- SERIES 7000 XV21434 102 CRABTREE ENGLAND

Tia Jim K