3 Gang switch question

[andemz]

Hi there all, just to say that i'm really enjoying reading everone's posts and reply's could stay on here for hours.

Question - you have a 3 gang switch. The far left switch shall operate the porch light 1 way only. The middle switch shall operate the hall light and be 2 way so that it can be operated from upstairs as well and the far right switch on the 3 gang shall operate the top of the hall landing. this also will be 2 way so it can be operated from down stairs and upstairs.

I don't find it difficult understanding how a two way lighting system works but have searched hi and low for a diagram or info on how in this situation a 3 gang switch is wired up for 2 way use on 1 switch, 2 way use on another switch and 1 way use on another of the switches.

can anybody shed any light. I am learning and am not attempting to do any of this. It's just that when i look around my house i can see clear electrical design issues, that impede on ease and practability of living.

Thanks in advance

 

[Big_Spark]

Adam, the switched are wired as if they are individual switches, they just go to the same box instead of seperate ones.

Connecting the switches is the same as connecting individual switches.

There are ways to complicate the matter, by sharing a loop feed at the switch (2 plate method) and linking the supply in the switch, however this is only usually done in conduit installations as you are not allowed to run a conductor on it's own, unless it is an earth conductor.

 

[andemz]

Thanks FWL

I just got a bit lost where you mentioned

by sharing a loop feed at the switch (2 plate method) and linking the supply in the switch

.

This is the first time that i've come across that one. I've read loads of posts and have gone through 2 books albeit it basic ones. New terminology can you elaborate on this a little more.

Oh by the way just having a good read of the post that you did in respect of the house that you went to where you were well impressed. I'd love to see some photo's of that sometime.

Anyway if you could clear that up for me that will be another thing learnt today.

 

[Big_Spark]

Adam, there are two normal types of wiring that electricians will use to wire lighting circuits.

Method One, this is the one you will normally come across in domestics and usually will be the method used when T&E is used to wire the circuit.

This involves taking the live feed (Live and Neutral) from the Mains to the first light point on the circuit, this Live/Neutral Pair then loop to each light on the circuit, continuous and unbroken. In order to switch the lights on/off, a pair (one cable) is taken from the cieling rose/light point, to the switch, this acts as the feed to the switch and from the switch. There are no neutrals at the switches.

This method is known as Three (3) Plate.

Method 2, usually found in conduit, trunking systems, but occasionally in other methods.

Here the Live and Neutral seperate, the Neutrals are looped between the light points as normal, but the Live goes to the switch, this is then looped to each switch point on the circuit, from the switch points a core will be taken back to the light and used to act as the feed to the light, there would be no permanent feed at the light point.

This method is known as Two (2) Plate.

There are variations of both systems, but that is usually when the circuit needs to meet specific requirements, like Double Pole switching, so the Live and Neutrals would be looped at the switch points with a Live/Neutral feed to the light. This system is often found in Military and specialist installations..like petro-chemical.

There are no hard and fast rules about which system is used. I have often 3 plated conduit systems, because it was easier to install the conduit to suit a 3 plate system..you need to look at jobs individually.

Please do not ask why they are 2 and 3 plate...I have never found a spark or engineer that knows, it is from the turn of the 20th century in the old DC supply days as I understand it.

 

[andemz]

very informative reply, i will chew on this one for a while. For me ease of living is key and design goes hand in hand with that.

 

[securespark]

FWL

Does not three plate refer to "L", "SW L" & "N" (ie three terminals), while two plate is just "SW L" & "N" (ie two)?