wiring

[PULSE]

I wanted to put a light in my loft with a switch so i was just going to tap into one of the roses from another room. The thing is the conduit is all metal and so are the roses the one i had a look at had 2 conduit pipes coming out of it one pipe had 2 black wires which were joined and a red wire which went into the other pipe. the second pipe had a white wire and the red wire, i was totally lost, the pendant was connected by connecting the blue to black and brown to white. Could someone please explain to me how i would tap into this wiring to add a light in my loft and a switch. Thanks

 

[securespark]

Sounds like you need a re-wire...

 

[notb665]

Why?

 

[Paul_C]

The conduit with the red and black will be bringing power in and the one with red and white will be the loop to the switch (i.e. the white wire is being used as the return from the switch). You would, therefore, tap power from the red and black.

This is clearly an older installation. Be aware that to tap into the conduit system and run an extension and do the job properly is a rather more difficult task than just adding T&E cable into a ceiling rose as on the typical modern system.

 

[securespark]

#As Paul says, this is an older install.

I can't remember how long ago white was used as a phase colour, but it is YONKS!

 

[Paul_C]

White was allowable under IEE Regs. until August 1964, when it was replaced with yellow.

I would think that this installation is likely quite a bit older than that though, unless the building was originally something other than a house.

 

[securespark]

Yes. I think when he says conduit, that to me conjurs up an image of 1920's - 30's with drawn clamped conduit.

 

[Paul_C]

That's what I have in mind as well: The conduit is a much thinner gauge than the steel conduit most people picture these days, very similar to the EMT used in the States where the protection of heavy-duty conduit is unnecessary.

I've come across quite a number of Victorian-era houses in my area where the sockets and other circuits have been updated over the years but the lights are still on original 1920s wiring.

 

[PULSE]

Believe it or not but i have lived in this house since it was built and that was in 1968. Also the two black wires are joined together and the red cable comes from the same conduit but then goes straight to the other without a join. how do i determin which black wire and shall i just split the red and a take a line from that using terminal block to join it up again. Thanks for all the help. I think when they built these houses they just used what wire was left from the American army camp that was originally here and just threw them up.

 

[ban-all-sheds]

I think when they built these houses they just used what wire was left from the American army camp that was originally here and just threw them up.

That would explain the white & black...

 

[securespark]

Indeed......!

 

[Paul_C]

Ah, so maybe it is American EMT then!

As black, red, and white would be the three main colors used in U.S. wiring, it does sound as though they might have used up the surplus, adapting to British usage by using black for neutral and white for switch lines.

Also the two black wires are joined together and the red cable comes from the same conduit but then goes straight to the other without a join.

One black will be connected back to the neutral and the other most likely continues on (doubling back on itself in the conduit for part of the run) to another lighting point.

The red wire has been drawn straight through the box as it is the live feed to the switch -- No need to break it as you need the switched live at the light, not the permanent feed.

To tap in at this point and run to another light, you would have to tap into that red wire to pickup your feed.