Commercial radial circuit

[Divspark]

Hi everyone looking to clarify something, had a tester onsite today testing circuits we've been installing the past few weeks, in his opinion he found fault with one circuit, we had wired a 30m radial circuit in 2.5mm 2core & earth fp200 on a c16 mcb. The cable was clipped direct throughout its entire run so according to the tables it should be rated 27amps, he said all radials feeding sockets should be 4mm and that it was in the regs, don't get me wrong we would normally cable in 4mm but seen as all we had was 2.5 and the table said 27amp we didn't see an issue. So my question is in all reality was he right ? And if so where in the big green book is the reg stateing it ?

 

[7029 dave]

2.5m lighting circuits, how the hell do you terminate them into accessories.?

 

[Tiny Spark]

And getting 3x 4mm into a socket sorts the men from the boys

 

[Plonker 3]

Place I used to work put in 4mm Rings and radials as standard.
It was basicly due to the size they could grow to and the amount of stuff that would be plugged in!

Its just the way the company like it, power circuits 4mm - lighting circuits 2.5 I can only assume that it's there preference and seen as the majority of time we fit to spec that's what goes in, the vast majority of circuits we do the cable will be overrated but like I say that's there decision !

Not a dig at the two people who have posted but, Obviously both companies have no idea how to design circuits properly.

 

[shanky887614]

2.5m lighting circuits, how the hell do you terminate them into accessories.?

they use click roses mate so easily.

ive had 3 in a click rose easily before (tri rated though)

 

[Tiny Spark]

2.5m lighting circuits, how the hell do you terminate them into accessories.?

Often we wire to "Greggs" as we call them, Clix sockets are another name, basicly they are sockets for light fittings, then the fitting itself will be wired with flex to the plug.
Makes changing and moving fittings much easier.

 

[dingledong]

32amp breaker?

He said they are using 16 amp breaker

 

[Guest77]

2.5m lighting circuits, how the hell do you terminate them into accessories.?

These days in industrial or commercial lighting LCMs or multigang PCRs are common place, one connection with a 3 core and earth2.5mm2 cable and everything plugs in, it is easy to use 2.5mm2 in these cases, very common today really.

 

[Tiny Spark]

Not a dig at the two people who have posted but, Obviously both companies have no idea how to design circuits properly.

It wasnt a design thing as such mate,
Basicly becasue the circuits were being continually added to and modified they were done in 4mm to allow for long runs etc.
Factorys dont tend to stay the same way for very long LOL

 

[Plonker 3]

These days in industrial or commercial lighting LCMs or multigang PCRs are common place, one connection with a 3 core and earth2.5mm2 cable and everything plugs in, it is easy to use 2.5mm2 in these cases, very common today really.

Pretty sure ire you could fit a 16mm in the terminals of the multi gang klik boxes the terminals are that big.

 

[Plonker 3]

It wasnt a design thing as such mate,
Basicly becasue the circuits were being continually added to and modified they were done in 4mm to allow for long runs etc.
Factors dont tend to stay the same way for very long LOL

Surely if length of run is a issue for several circuits then a sub main is easier to pull in rather than a whole load of cables?

 

[Guest77]

Pretty sure ire you could fit a 16mm in the terminals of the multi gang klik boxes the terminals are that big.

yes your right, you probably could

 

[Divspark]

Often we wire to "Greggs" as we call them, Clix sockets are another name, basicly they are sockets for light fittings, then the fitting itself will be wired with flex to the plug.
Makes changing and moving fittings much easier.

Yeh we use greggs or flex7s to be honest It's not bad with singles, but If we do an eml circuit and run fp then the answer would be with extreme difficulty

 

[Tiny Spark]

Surely if length of run is a issue for several circuits then a sub main is easier to pull in rather than a whole load of cables?

Not really, Just to give you a example you may have a large office with say 6 rows of desks spread over the office on 1 ring main, But in 6 months time you may have 12 rows of desks all on the same circuit.
Another 6 months and you may have 1!

Most modern factorys change very quickly, I used to spend most of my time changing circuits I had only installed or modified a few months previously!

 

[Plonker 3]

How many sockets is irrelevant, it's all about the loading. Besides if changes are that frequent why not fit Busbar trunking to tap of making any future alterations a lot easier.

 

[Tiny Spark]

That costs more money in the short term

Everything is installed with 2 things in mind - 1) Ease of alteration and expansion 2) As cheap as possible.

We typically used Dado trunking in the offices so we could easily relocate and add sockets, data etc and 2 compartment Galv trunking out on the lines.

Lighting would be done in the way described above with Greggs and celing clips

3 phase supplys and everything else would ususaly be put in to order as one off jobs like you would normally.

I must admit though, The amount of times we had to move production machines Bus bar would of made my life soooo much easier!

 

[Divspark]

We tend to use bus bar trunking and floor boxes for offices etc that way it's a simple move rather than rewire.

And they tend to apply there 4mm rule to everything ! I've installed dedicated fused spurs for wifi routers in 4mm but again that's fitting to their spec.

 

[guest119]

All this talk about Greggs is making me hungry.

Boydy