Lighting Ring Circuit, Why???

[Gavin John Hyde]

On a job today to work out plans and discuss options with customer for a series of down lights in dining room and kitchen. went to do a few tests to check existing cables were okay and I open up the CU to discover lighting circuit installed as a ring using 2.5 T&E. This is on just the downstairs light circuit, the upstairs is conventional radial in 1.5mm


i suspect a DIY'er has gone to work a few years back as its old colour cables, the CU is poorly installed with cables all over the place inside poorly terminated. Couple bought the house in 1999 and no significant work has been done since so looks Pre part P DIY'er nonsense.

Never actually come across it myself before, only heard about it.

Question is why install it as a ring though??

Beyond this instance using 2.5mm which suggests its all somebody had to hand and didn't want to go get some 1 or 1.5 i see no real point. it means you have to run the cable back to the CU from the last point on the circuit. termination is a bit trickier on the space side too.

Not aware of any regulation that it violates though..

Anybody else come across this or aware of any regs it violates?

 

[Leesparkykent]

Come across loads of 2.5mm lighting circuits in commercial installs.... Normally singles in trunking and conduit though. Seen a few done as rings and I would assumed to negate volt drop. Serves no purpose in a domestic installation though. As long as the connections are sound then there is no violation of regs as long as the OCPD isn't over 16A.

 

[Deleted member 9648]

No reg against, but it suggests an installer with a lack of knowledge. Be careful if you are carrying out work on the circuit. Could be a can of worms.

 

[Dave OCD]

Seen a few lighting rings, all 1 or 1.5mm though. Found in the past when each 'leg' has been connected to separate RCDs on board changes.... On the other hand I once found a power ring with the respective ends terminated into individual 15a rewirable fuses.

 

[Gavin John Hyde]

No reg against, but it suggests an installer with a lack of knowledge. Be careful if you are carrying out work on the circuit. Could be a can of worms.

Customers are thinking about replacing downstairs light circuit as its poorly installed and given they are refurbishing most of the house and having the old floorboards upstairs replaced with the big chipboard panels, it provides a good opportunity to do the work, quickly with minimal mess, Much happier with this than piggy backing on some diy'ers handiwork.

 

[Leesparkykent]

Customers are thinking about replacing downstairs light circuit as its poorly installed and given they are refurbishing most of the house and having the old floorboards upstairs replaced with the big chipboard panels, it provides a good opportunity to do the work, quickly with minimal mess, Much happier with this than piggy backing on some diy'ers handiwork.

Perfect opportunity to do it then.

 

[davesparks]

Ring circuits for lighting can reduce voltage drop and for critical circuits such as emergency lighting circuits fed from central batteries or static inverters allow for redundancy should a fault occur.

 

[westward10]

Without looking at the latest copy you could do this for fire alarm sounder circuits where the minimum requirement is two circuits but you could use one if it were parallel. On my 2400 project many years ago I used a "ring" on one of the lighting circuits because as with many of these projects you often get a circuit with stretches convention.

 

[Midwest]

Customers are thinking about replacing downstairs light circuit as its poorly installed and given they are refurbishing most of the house and having the old floorboards upstairs replaced with the big chipboard panels, it provides a good opportunity to do the work, quickly with minimal mess, Much happier with this than piggy backing on some diy'ers handiwork.

In these circumstances, I'd think about rewiring the lot. But that's my own thoughts on such refurbishments.

 

[Simonslimline]

All the commercial projects I have been on the lights are generally wired in 2.5mm2 either in 6491B in trunking/conduit or SWA etc. Not as an RFC though as of yet!

 

[electric al]

The lighting circuit in my house is wired as a ring and covers the whole house.