Moving Consumer Units

[sdcoomber]

Generally, we would use the Wiska box. A couple of times apprentices have asked whether it would be OK to run a 6mm cable and join to the original ring mains in the Wiska. If the Wiska box is accessible for future R1+R2 testing, is there any reason this can't be done? My instinct is to say "don't" but I can't come up with a reason why (and it is true that a line of 6mm cables is neater than a clump of 2.5mm).

 

[westward10]

For testing purposes it would be far better to keep the ring finals at the consumer unit.

 

[brianmoooore]

The type of circuit you would be creating is commonly known as a lollipop, and while meeting all regs, wouldn't be popular with anyone testing, as westward has said..

 

[Gurnatronics]

Take it splitting the ring and downrating to 2x 20A radials is a no go either?

 

[westward10]

Take it splitting the ring and downrating to 2x 20A radials is a no go either?

Why would you do that.

 

[Gurnatronics]

Easier to test two radials than a ring. Im not so keen on rings these days

 

[Lucien Nunes]

You might not like testing rings but that's not in itself a good reason to change the design; there are situations in which rings are superior, or perhaps I should say more specifically 32A circuits are superior to 20A and if it's in existing installation as a ring it has to remain a ring if one is going to keep the 32A OCPD.

If you have lots of small loads that are evenly distributed, 2x 20A gives an extra 8A in total to share out compared to 1 x 32A, and on an RCBO board the leakage is divided between two devices so possibly less risk of nuisance tripping. But you can't (or shouldn't) run 2 x 12A loads on either of the 20A radials, you've got to ensure one is on each circuit. You can run both anywhere on a 32A ring. Each configuration has advantages and disadvantages but the specific task of relocating a CU wouldn't normally involve an appraisal of those and reconfiguring the circuits.

Returning to the original point of whether it's acceptable to form lollipops, I would prefer not to. I can't see that it's a big deal to run a few more cables and the nuisance of having to test from two different locations isn't justified by the very minor saving in space and cost in the terminal box.

 

[pc1966]

Easier to test two radials than a ring.

Also poorer fault coverage?

For example, many only do the R1+R2 test on a radial to verify (dead) that Zs will be met, and they should also check polarity at each socket as well. But you only know your worst-case R1+R2 if you also know the end socket, which for an EICR is unlikely. Though if you have just installed it then you would know.

If the radial is "pure" (i.e. only ever two cables at each accessory so no branching tree-like) then an end socket test gives you good coverage of the whole circuit, but in practice you might have a tree-like arrangement and so you have to test the "branches" to know that all are good.

Do you test RN+R2 as well? Probably not.

Where as for the RFC you are required to test all three: r1, r2, and rN and that gives you good knowledge of all circuit's connections are tolerably good from r1 and rN being practically identical, and r1/r2 ratio matching the CPC/L conductor size ratio (usually, assuming no metal bonding from more than one socket).

True, if there are spurs you do not have coverage of them in the end-end test and also for EICR probably no knowledge of where they might be, but when you do the socket polarity test using the figure-of-eight approach it gives you a very good indication not only of any possibly bad switch/contact in a socket, but also the likely existence of a spur from measured resistance not being identical to all other sockets.

Personally I don't like spurs for exactly that reason: they breaks the excellent fault coverage of the end-end test which is convenient to do at the CU without knowledge of the physical route and order of accessories.

 

[Dustydazzler]

Keep as a ring circuit

Not a big fan of Lollypop circuits

if the ring is not a ring a ding ding then may be consider 2 radials if you can't complete the ringer

 

[davesparks]

Easier to test two radials than a ring. Im not so keen on rings these days

Easier does not make something better.

 

[pirate]

sonetimes easier can be better

 

[LastManOnline]

Easier to test two radials than a ring.

radials are easier in virtually every respect.

Im not so keen on rings these days

You are part of a growing group.Visit this forum in ten years and you can be pretty confident you will be in the majority.

 

[brianmoooore]

If AFDDs don't come down in price, we might be putting whole properties on a single ring.

 

[DPG]

If AFDDs don't come down in price, we might be putting whole properties on a single ring.

Don't say that - you'll wake somebody up!!

 

[davesparks]

radials are easier in virtually every respect.

You are part of a growing group.Visit this forum in ten years and you can be pretty confident you will be in the majority.

Again, being easier does not necessarily make something better.

A growing group of what? People who don't understand the advantages/disadvantages of all available circuit types? people who find rings too difficult to understand? People who can't cope with having more than one type of socket circuit to choose from?

 

[Dustydazzler]

If AFDDs don't come down in price, we might be putting whole properties on a single ring.

6mm radial for everything would be 'Easier'

 

[ipf]

Again, being easier does not necessarily make something better.

A growing group of what? People who don't understand the advantages/disadvantages of all available circuit types? people who find rings too difficult to understand? People who can't cope with having more than one type of socket circuit to choose from?

Just more dumbing down to accommodate the workforce, I guess.