Three plate & loop in methods

[alexsinger]

Hi,
I'm an electrical apprentice and wanted to know why the loop in method is preferable in industrial applications to the three plate method. I've learnt these methods at college but it seems that people at work think they're the same thing.

Thanks

 

[Marvo]

Please check this out if you're currently on a training course. Announcements - Trainees Only

 

[ackbarthestar]

I'm not a trainee so I can't gain access.
Wiring in conduit is called the 2 plate or conduit method and loops the phase conductor at the switches and the neutrals at the light fittings. Its called two plate because there are only two connections. I'm sure somebody else knows the history why its called 2-plate

Wiring using T&E uses 3-plate because there are three connections where both the phase and neutral are looped in at the same position. Often at the ceiling rose but more commonly at the switches.

 

[ImpededLoop]

Three plate is often used when using twin and earth cables.

In commercial/industrial single cables in trunking or conduit are often used so loop-in is normally used to save cable and the number of terminations.

 

[ackbarthestar]

Reading my last post, it needs a little more clarification.
In both 2-plate and 3-plate you will need to add the switch connections. Do not confuse this with the cpc/earth connections which be there for all the terminations

 

[baldsparkies]

Practicality, Economics, plus industry recognised installation methods all add up to a difference between commercial and domestic installs.
3 plate, like loop in as you put it, all have there place and applications.
I remember a guy who had spent a lifetime house bashing working with us on a commercial install.
When he looked at the conduit ends with 3 single cables coming from both 2 way light switches.
He made the mistake of smugly stating that some idiot had wired them up wrong.
Had strapper's only installed both ends with no switch wire "he says"
I had to draw a diagram for him before he could see how it worked.
The other guys weren't so forgiving, especially the sparks who had pulled the singles in.
Don't be harsh I said, he might not be much of a sparks but I bet he can lift floorboards, move furniture and re lay carpets better than any of us.

 

[7029 dave]

I'm not a trainee so I can't gain access.
Wiring in conduit is called the 2 plate or conduit method and loops the phase conductor at the switches and the neutrals at the light fittings. Its called two plate because there are only two connections. I'm sure somebody else knows the history why its called 2-plate

Wiring using T&E uses 3-plate because there are three connections where both the phase and neutral are looped in at the same position. Often at the ceiling rose but more commonly at the switches.

That is an first class answer to the op.