Ring vs Radial : Identification.

[pc1966]

Although, when you think about it, with 2 rings and 1 radial on a single device it only only takes 2 snips and a bit of trimming and you have 5 radials on a single protection device.

That would be valid so long as the OCPD is suitable for the use.

So with 32A and 2.5mm it should be a RFC only, but with 4mm it could be a radial on 32A (in many cases, but subject to method for CCC)

If you have a dubious mix of radials and spurs that are not OK then simplest safe option is to drop OCPD to 20A as then it protects the 2.5mm however used.

Sometimes you would see RFC on 20A fuse wire if the supply Ze was too high tor meeting 0.4s disconnection, etc. While not as useful in terms of diversity as 32A (i.e. number of mixed loads up to 13A supported) it works just fine if that limit is respected.

 

[brianmoooore]

When you see two lines on one MCB that could be either a ring or two radials.
The only way to determine which is through testing. Is that true?

If the MCB is 32A and the cable is 2.5mm2, then it should only be a RFC if there are more than two sockets.
If there are three lines, there should only be one socket on the spur, and the rest on a RFC.
Testing for a ring, at its most basic, is disconnect one leg, turn the power back on, and check that all the sockets still work.

 

[Ray Pooley]

If the MCB is 32A and the cable is 2.5mm2, then it should only be a RFC if there are more than two sockets.
If there are three lines, there should only be one socket on the spur, and the rest on a RFC.
Testing for a ring, at its most basic, is disconnect one leg, turn the power back on, and check that all the sockets still work.

Thanks for your input.

 

[John-SJW]

So three radials (or more?) can come off one OCPD 's terminal in the CU. That has been determined on this thread.

My Question. A radial can be spurred off a radial, but can a radial be spurred off radial spur?

 

[nicebutdim]

So three radials (or more?) can come off one OCPD 's terminal in the CU. That has been determined on this thread.

My Question. A radial can be spurred off a radial, but can a radial be spurred off radial spur?

It can.