lighting question

[thomo27]

Evening all

If you have 3 sets of cables at a lighting point for example mains in , mains out and a switch cable how many browns would you expect to receive 240 V against when measured to earth ?

 

[Steve]

One.

 

[Spark123]

Do you mean connected up?
You should have 240v on the 3 which are joined (loop) and possibly on the switch return which could be blue with a brown sleeve or brown.

 

[thomo27]

One.

Hi Steve thanks for your input Im hoping you might be able to explain why as I was thinking 2 , the reason I was thinking 2 is if we imagine the first brown from the CU (I will call this mains in) Id expect to see 240 V and also on the mains out brown so Id have thought 2 , can you advise where im going wrong ?

cheers

Ste

 

[333rocky333]

The mains out is not live till it is connected to the mains in.
Lighting not usually a ring in domestic .

 

[thomo27]

The mains out is not live till it is connected to the mains in.
Lighting not usually a ring in domestic .

if the mains in brown and the mains out brown are both connected in the loop terminal of the ceiling rose then I cant see how they arent both 240 V against earth ? Im not disagreeing with you btw Im just not understanding

 

[Steve]

Once they are connected, yes, both browns are live, as is the feed to the switch. But disconnected, you will only have one live wire.

 

[thomo27]

Do you mean connected up?
You should have 240v on the 3 which are joined (loop) and possibly on the switch return which could be blue with a brown sleeve or brown.

Yes connected up - so 3 cables mains in , 3 cables mains out and 3 cables from the switch

I thought 2 as the mains in would be 240 v from the CU and I thought the mains out would also be 240 as it flows out

cheers

 

[thomo27]

Once they are connected, yes, both browns are live, as is the feed to the switch. But disconnected, you will only have one live wire.

Oh dear I cant believe how confused I have been about this all weekend , the issue came about in ref to the 'lighting fault' thread down the page and whilst the line conductors were disconnected we were getting glow from the Volt stick on 2 of the 3 lines when the switch was off and I couldnt see what the problem with that was

I do now lol

 

[thomo27]

Do you mean connected up?
You should have 240v on the 3 which are joined (loop) and possibly on the switch return which could be blue with a brown sleeve or brown.

Yes connected up - so 3 cables mains in , 3 cables mains out and 3 cables from the switch

I thought 2 as the mains in would be 240 v from the CU and I thought the mains out would also be 240 as it flows out

cheers

I actually meant disconnected lol this is where the confusion has come about admin can we forget this thread ever happened

 

[Spark123]

You only have 240v on any part of the system which is energized.
If you have all 3 cables hanging out of the ceiling (with each 3 wires in chock blocks) then when you energize the system only the live in will be connected to the mains so is the only cable you should see 240v on with respect to earth.
As the other 2 cables are not connected to a source they should test dead.

 

[securespark]

No. You started it, so you'll just have to live with the humiliation for the rest of your natural.

 

[Taylortwocities]

Indeed, and topics like this stay on here FOREVER

 

[thomo27]

Indeed, and topics like this stay on here FOREVER

 

[securespark]

TTC, you forgot the evil laugh...

Ha, ha, ha, ha, haaaaaaaaah!!!!