diy

22409 readers

2 users here now

Finally, a comm for that one user who hand-makes longbows. This ones for you, comrade.

founded 5 years ago

MODERATORS

gaycomputeruser@hexbear.net

Wake@hexbear.net

Q: Wiring up a dimmer switch to an old house (hexbear.net)

submitted 2 days ago* (last edited 2 days ago) by aanes_appreciator@hexbear.net to c/diy@hexbear.net

7 comments fedilink hide all child comments

TLDR: is a Neutral wire in a "live + neutral + ground" setup the load output wire or a neutral wire when doing light switches?

My house is ca. 1907 for context, and the only wires I've got are:

Red (Live), tested with multimeter.
Grey (Neutral..?), was connected to common terminal of old (traditional) switch
Exposed (Ground?) Connected to terminal housing.

My new dimmer supports "with or without neutral" circuits:

but what confuses me is how the 2nd wire is a neutral line, but clearly is being used as common; should this be connected as neutral, or do I have a "no neutral" circuit setup?

I've got some old wiring from the cellar to demonstrate what I think is correct, including some ground wire taped up to connect the L+N terminals as the circuit describes:

(NB: Brown is Live, Blue is Neutral, this wire postdates the house by a LOT)

all 8 comments

sorted by: hot top controversial new old

[–] aanes_appreciator@hexbear.net 3 points 2 days ago

2nd Note: I've just checked and it's supposedly not a good idea to stuff the wires into the terminal together. I'll pop to the shops and get a pigtail connector.

[–] trompete@hexbear.net 2 points 2 days ago* (last edited 2 days ago) (1 children)

I mean it has to be the load output, how else would that work. In order to make a circuit, it needs to be live - switch - lamp - neutral. If you just had live and neutral, the circuit would be live - switch - neutral, which I guess would make a funny let's blow the fuse prank switch or something.

[–] aanes_appreciator@hexbear.net 1 points 2 days ago

Yeah I didnt really think that through lmao. and to think i was considering physics at university...

[–] Yllych@hexbear.net 2 points 2 days ago* (last edited 2 days ago) (1 children)

Not too familiar with British wiring, but I am thinking your brown wire is a switch leg that goes directly to the light itself. If you go to the light you're wanting to control, do you have the same red and brown wire? You could use your multimetre to ring the wires out and determine what is going where to be certain.

[–] aanes_appreciator@hexbear.net 1 points 1 day ago

I did more researching and you're right. neutral is used as the switch leg as you call it. Here's it's called a "common" line. Some circuits will have a second live wire that takes the place of "common" so the Neutral would be used in that case, but the naming conventions confused me 😅

[–] LeninWalksTheEarth@hexbear.net 2 points 2 days ago* (last edited 2 days ago) (1 children)

at the minimum every outlet you see will have a hot and neutral. i only see two wires and a ground(the exposed copper wire), so the two wires would be a hot and a neutral. Newer wiring can have a 2nd hot. https://inspectapedia.com/electric/0588s.jpg

I had knob and tube in my house and its literally just a hot and neutral no ground. Yours is at least modern enough with the ground wire that's in the sheath. Some ground wires are connected to the metal outlet box, but that only works if that box is also grounded.

im no electrician, i did replace all my 3 prong outlets that didnt have a ground with GFCI outlets(makes it slightly safer). Just make sure to turn off the breakers. I just watched youtube videos and asked questions on the askelectricians reddit. yea, reddit is still useful.

the back of the outlet should say where the hot and neutral goes

[–] aanes_appreciator@hexbear.net 2 points 2 days ago

Yeah the house is an ex rental so the wiring will have been redone to meet regular council inspections, so it's more modern than that! Useful diagram btw.

Good to know I'm not crazy thinking that it's DEFINITELY a neutral wire. I think the UK's terminology is a bit of an arse because in switch circuits the neutral appears to be called a "common".. i think

In the end, I did just do as the pic showed but with clips to combine the live terminals. Annoyingly it both made a shite connection and the lack of load on neutral made it flicker a bit so it's back to the flicker switch for now.

I'll come back to it when I've got those hits sorted :) ty!