Faulty Common On Three Way Switching

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thinker

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I have been trying to get my 3 way down stair hall switching to work, I have eventually narrowed the problem down to a non viable common between the intermediate switch and the end of line switch, is it possible to use the earth suitably sheathed to replace this duff common?

Box 1, single two way switch near lounge door.

FFB Live +yellow from 6243y in 1 way portal

Live from light + blue from 6243Y in 2way portal

FFB Negative and light negative in electrical connector

Live from 6243y to common.

all earths to back of box.

Box 2 intermediate. Bottom of stairs. single two way switch (adjacent to 3 way box 3 1st floor landing light .)

Both reds (Commons) connected via electrical connector . ( The red to switch three appears duff.)

yellow from box 1 into top portal 2 bottom portal 2 has yellow to switch 3

Blue from box 1 into top portal 1. Bottom portal 1 has blue to switch 3

earth to back of box

Box 3 top of stairs one half of 2 gang 2 way switch ( the second gang is the ffb for the 1st floor landing 3 way)

Yellow from box 2 (intermediate) into portal 1.

Blue from box 2 (intermediate) into portal 2

Red into common (Duff)

earth to back of box with others from other gang.

What do you think?

 
I have eventually narrowed the problem down to a non viable common between the intermediate switch and the end of line switch, is it possible to use the earth suitably sheathed to replace this duff common?
I'm sure you could as long as you pull through another earth wire to replace the one you'd no longer have :) .

 
No one in the trade would do that , Thinker . Suggest you "Think" about it before you do that , it would become a bare , uninsulated live conductor .

This method is usually left with BG sparks /plumbers when they wire roomstats with 2core cable then find they need a neutral.

 
Under no circumstances use a bare earth wire as a live conductor. Basic protection requires that live conductors in multi core cables should be insulated along their entire length. Remember electrical protection is provided by the insulation and mechanical protection is provided by the sheathing. In normal use an earth wire carries no live current, so it only requires mechanical protection. All Line and neutral conductors do carry live current so they both need basic electrical protection as well as the mechanical protection.

Doc H.

 
There has been a 2 way system from box1 to box 2 left like that by the electrician, he said he needed a special box to finish the run -that was 4 years ago, I figured it was the intermediate switch that was the missing link so I purchased it myself and copied the existing satisfactory 3 way light for the landing, but nothing happened so I set about passing power through each wire and testing with my screw driver ant the end of the run and that is how I know the common from intermediate to end is duff. This is all modern wiring with proper earth trips etc I wonder If I could pinch a common connection to the near by separate 3 way.

 
Not the dreaded neon screwdriver ]:) ]:) ]:) ..

Your suggestion is what i was thinking. Pick a feed up from the other two way swich. This would need reconfiguring to the other ends connections and probably would not work as they will be on different circuits. I think you need a good electrician to properly test this out, it may be cheaper in the long term

 
Not the dreaded neon screwdriver ]:) ]:) ]:) ..

Your suggestion is what i was thinking. Pick a feed up from the other two way swich. This would need reconfiguring to the other ends connections and probably would not work as they will be on different circuits. I think you need a good electrician to properly test this out, it may be cheaper in the long term
Well if neutrals are in the box also then maybe different circuit, could be lucky though and it maybe on the same, fingers crossed !!!!!

 
its very rare that a one core from a twin or 3 core goes missing. Saying that it does happen.

I imagine you either have it connected up wrong or a core missing as you say.

What you really need is an electrician. If you have a core missing/damamged, why? Why has it not tripped the breaker? Could you have a live screw poking out of the wall? Could your wall potentially come live if its damp? Yes it happens!

 
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