Old regulation - maximum 10 roses per lighting radial

[phatboy]

Hi,

I couple of times I have seen installations where there are 2 wires into the terminal of a fuse holder on a lighting circuit. Someone mentioned an old regulation about having a maximum of 10 roses/lights on a circuit.

In the last case, a whole house was wired into 1 fuse, but with 2 cables. 1 of the cables served everything, with the exception of a single room, fed by another.

Was this an old regulation? All the properties I have seen it in were built in the 70's and 80's

Thanks

 

[EFLImpudence]

It was probably just a typical guide from the OSG for those who didn't want to think because lighting points were counted as 100W.

 

[kai]

It was a good idea in principle, as when a blown lamp took out the breaker, it did not place too large an area into darkness.

Splitting the lighting into different circuits makes a better option.

 

[securespark]

In my experience of the good old days, the ROT was maximum 12 (ie 100 per point, 5A fuse). But in practice (again, in the good old days, before multi-lamp fittings, down lighters etc..) in most houses you got away with 10 ceiling roses / batten holders.

 

[plugwash]

I've certainly seen 10 lighting points per circuit mentioned before though I think it was only a guideline not a reg.

5A@240V is 1200W. 10 points at 100W each is 1000W, add in that some points may have large fittings with more than one bulb or a bulb above 100W and 10 points per circuit seems reasonable.

I suspect the "two wires in one fuse" case indicates that there were originally two circuits and that at some point in the installations life they were merged to free up a way in the CU for something else.

Of course with the current fetish for CFLs it's less relavent nowadays.

 

[OwainDIYer]

In the last case, a whole house was wired into 1 fuse, but with 2 cables. 1 of the cables served everything, with the exception of a single room, fed by another.

It may have just been easier to wire it up that way. No reason why a radial (or a spur on a ring) shouldn't branch off from the consumer unit provided the terminals are able to accept all the cables.

 

[GaryGarden]

It was a good idea in principle, as when a blown lamp took out the breaker, it did not place too large an area into darkness.

WTF
Have you been on the funny fags this afternoon, if I've read it correctly you are saying that if TWO circuits are connected to one breaker and the breaker gets taken out then one circuit will still function????

Are you confusing an MCB / Fuse with an RCD on a split load or dual RCD board?

 

[AdrianUK]

Or, there WERE two lighting circuits ..... BUT the classic borrowed neutral on the stair light meant that they had to be combined onto one MCB because a later sparks couldn't get a retro fitted RCD to hold in & he was too lazy to find and sort the borrowed neutral.

As a point of interest..... it doesn't matter how many wires come out of a single MCB its still, technically, by the definitions in the regs book, a SINGLE circuit

 

[AndyPRK]

A borrowed neutral doesn't mean it has to be on the same MCB, only the same rcd.

I would like to think that 2 cables would be upstairs and down stairs lighting.

 

[PrenticeBoyofDerry]

As mentioned in several previous post the 10 lamps would be concerning 100 watt lamps on a 5A circuit. Which would be very close to it's maximum loading and if discharge lighting were to be used a 1.8 factor would have been used.
I believe once the 6A lighting circuit became more common the maximum lamps recommended was 12.
With the lower wattage lamps now norm, it would all be down to design rather than the rule of thumb.

 

[phatboy]

This is virgin installations, in an original 1970's / 1980's Wylex boards. Only circuits in one was

-Sockets
-Lights
-Water Heater
-Cooker

So certainly none have been combined to allow extra ways and not an RCD in sight!

 

[RF Lighting]

I was taught 10 points per circuit when I was an apprentice, but have never seen it anywhere in writing.

 

[JohnW2]

I was taught 10 points per circuit when I was an apprentice, but have never seen it anywhere in writing.

I would imagine that, in the days that guidance was around, it was probably not particularly burdensome in domestic settings, since I doubt that your 'average' house usually had more than 10 lights, did it?

Kind Regards, John

 

[phatboy]

I was taught 10 points per circuit when I was an apprentice, but have never seen it anywhere in writing.

I would imagine that, in the days that guidance was around, it was probably not particularly burdensome in domestic settings, since I doubt that your 'average' house usually had more than 10 lights, did it?

Kind Regards, John

3 bedroom house had 11 in this case.

Kitchen
Lounge x2
Hall
Outside front
Toilet
Stairs
Bathroom
Bedroom x3

I'm surprised how much comment this thread has generated

 

[JohnW2]

3 bedroom house had 11 in this case.
Kitchen, Lounge x2, Hall, Outside front, Toilet, Stairs, Bathroom, Bedroom x3

Fair enough. Back then, the sort of house I was brought up in usually had only one light in the lounge (but often a separate dining room to 'cancel' that), no 'outside front' light and often no separate toilet - so, compared with yours, probably 8, 9 or 10. I would think that significantly more than 10 lights would have been unusual, until one moved up to larger (4+ bedroom) houses.

Kind Regards, John