Radial circuit. Star from wagobox or daisychain

[jase31]

Can a radial circuit be installed by taking the supply to a location into a wagobox, splitting and dropping down to 2/3 sockets, or is it preferable to daisy chain from each socket (uses more cable, and further voltage drop)

 

[telectrix]

can't see a problem, but i would prefer to daisy chain the sockets, if only to have all joints in the sockets.

 

[jase31]

I dont like juction boxes, and daisychain is my preference, but on downstairs drops, a star uses less cable that going up and down daisychaining.

 

[telectrix]

used to be common years ago, especially on lighting. was called spider wiring, or seek out the junction box.

 

[tigerpaul]

If you wire with a JB as a "spider", you will end up with multiple end of lines. Therefore you need to test r1 + r2 and loop impedance numerous times for one circuit.
For this reason, I believe a regular radial "daisy chain", is better.

 

[Deleted member 26818]

I've just come accross a similar situation when conducting a PIR.
At first glance I thought it was a RFC, as the CPD was a 30A rewireable, and there are two 2.5mm² T&E cables.
When I inspected the socket-outlets each was supplied by just one 2.5mm² cable except for one in the living room directly above the CU.
Without tearing up the carpets and floorboards, I can only assume that the sockets have been wired in a spider configuration.
I suppose it is possible that the circuit has been run as a ring, and each socket-outlet spured off the ring using a JB?
Very strange. Obviously I've changed the CPD to 20A.

 

[telectrix]

I suppose it is possible that the circuit has been run as a ring, and each socket-outlet spured off the ring using a JB?

seen that on a few jobs from the 60's and 70's. basically you have a RFC with unfused spurs, but as long as there's only 1 outlet on each spur, it would comply with a 32A MCB .the problem would arise when someone spurred additional sockets from a spur without fusing down. replacing the CPD with a 20A is a wise move. done the same in our gaff, where over the years, spurs have been extended.

 

[Deleted member 19807]

did you do an end to end test at the DB to test for a ring?

if it was indeed a ring then the 30a fuse would have been fine.

 

[Deleted member 26818]

did you do an end to end test at the DB to test for a ring?

if it was indeed a ring then the 30a fuse would have been fine.

I kind of fibbed slightly when I said that I was conducting a PIR, I haven't really started it yet.
I was actually asked to add two socket-outlets, one in a bedroom and the other in the kitchen.
The one in the bedroom was to be spured back to back with one in the living room.
When I removed the socket front in the living room, to drill through the wall, I noticed that there was only one cable, so at first thought it was already spured.
I thought that I would have a look at the other socket in the bedroom to see if I could spur from there instead.
After discovering just the one cable at this socket, I decided to check out all the other sockets 9 in total.
Eight sockets have only the one cable, and just the one directly over the CU has two. There is also an old 6mm² feed to an FCU which was for an immersion heater (long since removed) on the same circuit.
I quickly conducted some Zs test at each socket, and found such a disparity of readings that it suggests the sockets are spider rather than on a ring. Readings varied from 0.17Ω to 0.55Ω.
I then suggested that I should return to conduct a PIR, which has been agreed.
As I charge a fixed price for a PIR, I didn't want to get the work of the sockets mixed up with the price for the PIR.
So I finished the sockets off, changed the CPD to 20A, and will return tomorrow to conduct the PIR, when I will conduct the tests at the DB, and also take a look at the mess in the loft.
Obviously I won't bother re-testing the Zs at the sockets, as I've already got those results along with the Ze of 0.09Ω and the PFC of 3.77kA (TN-S).