New Regs on Spurs?

[Doctor D.]

It is now many years since I passed my City & Guilds 224, 232 and 236 and I don't pretend to be up to date with the Regs.

However, a young upstart :-) son of a friend is currently training as a sparky at a local hospital. He tells me that it is now acceptable to run as many spurs off spurs as you like provided that all the outlets are in the same room. I was very sceptical that this was the case (although being New Year we had all had several shandies) and wonder if any of the learned gents on this site can reassure me?

I presume it is also still the case that you must not have more spurs than ringed outlets on a ring main? If I have got sufficiently out of date to have missed both of these fundamental changes I fear it's the end of the world as I know it!

I do remember at college being given earache for calling a ring final sub-circuit a ring main, and for calling MIMS by the usual name (to me) of Pyro! I was forcibly lectured that you only ever found a ring main as part of the supply network operated by the electricity board as it was then.

[Andy Hall]

Spurs off of spurs? No.

He had had too many shandies.....

For a BS1363 ring final circuit:

The number of unfused spurs fed from the ring circuit must not exceed the number of sockets or fixed appliances connected directly in the ring.

Each non-fused spur may feed no more than one single or one twin socket, or no more than one fixed appliance.

You can put in a fused connection unit with 13A fuse and connect a spur downstream from that. On such a spur, you can connect as many socket outlets as you like and even in a daisy chain.

There is more flexibility regarding radial final circuits. With appropriate cable size and fuse/circuit breaker are used. You can have as many outlets as you like within diversity constraints.

I wonder if there are separate and special rules in hospitals, although I haven't read of them. If anything, I would expect rules to be more conservative, though.

To email, substitute .nospam with .gl

[Chris Oates]

So you should be. one spur from from one ring socket feeding (max) a twin socket.

correct

Only exception is taking a fused spur (13-16Amps) from a socket which can feed unlimited sockets but IIRC only in a 50 metre square area

possibly correct

Oh dear..I called it MIC

but they never did that ??..isn't everything spurs

[Dave Liquorice]

Depends how you define "ring". The very general local layout of the

11kV distribution round here is: +-----------------+ / \ NC NO 33kV SS --NC-------------NO--+ NC NC \ / +-----------------+

Note the normally open (NO) and normally closed (NC) switches, there is no closed ring as such but any one point can be fed from either direction from two other sources by operating the switches. There are numerous single phase "spurs" feeding either single buildings or groups of buildings. The above is the main 3 phase "backbone" of the distribution if you like.

[PoP]

Oops! I'm in trouble then. I just installed a triple socket in a cupboard upstairs a couple of days ago.

Hmm, the triple socket appears to have a fuse on the front, thus possibly combining a fused spur with the triple socket. Maybe I'm alright after all.

When my son was in hospital for 3 months in 2002 I gave him my laptop so that he could play games (a hospital isn't a grand place for someone to be wired to a bed in traction). The nursing staff wouldn't allow that until the on-site sparky had checked it out, so you are right about the additional dogma.

In this particular case I'm happy that they have some extra red tape.

PoP

Replying to the email address given by my news reader will result in your own email address being instantly added to my anti-spam database! If you really want to contact me try changing the prefix in the given email address to my newsgroup posting name.....

[Jerry.]

Surely that was just a case of PA test and making sure the unit wasn't going to cause anything else to fail, it might not have anything to do with fixed wiring reg's IYSWIM ?

[ARWadsworth]

That does not a surprise me. A student nurse I know had to have all her electrical items in her halls of residence room PAT tested.

-- Adam

adamwadsworth@(REMOVETHIS)blueyonder.co.uk

[Chris]

A lot of (general manufacturing) companies we deal with require any electrical equipment we carry to be PAT tested before we are allowed on site. I'm sure our H+S manual requires the same for contractors bringing equipment on to our site (whether it is enforced is a different matter :-))

Chris

[Huge]

I cam back from lunch at work once to find my personal CD player had been PAT tested, and the plug had been changed... All silently, invisible & free. I was impressed.

[Owain]

"Andy Hall" wrote | >However, a young upstart :-) son of a friend is currently training | >as a sparky at a local hospital. He tells me that it is now acceptable | >to run as many spurs off spurs as you like provided that all the | >outlets are in the same room. | Spurs off of spurs? No. ... | There is more flexibility regarding radial final circuits. With | appropriate cable size and fuse/circuit breaker are used. You can | have as many outlets as you like within diversity constraints.

I strongly suspect that the hospital is wired with radials, one per room. to minimise the affected area in the event of an MCB tripping. The 'same room rule' may be to enforce phase separation

Owain

[Owain]

"Doctor D." wrote | I do remember at college being given earache for calling a ring | final sub-circuit a ring main, and for calling MIMS by the usual | name (to me) of Pyro!

When I were a lad it was MICS

| I was forcibly lectured that you only ever found a ring main as | part of the supply network operated by the electricity board as | it was then.

Ring mains quite widely used in industrial buildings for supplying busbar takeoff points or Branch Distribution Boards.

Owain

[Doctor D.]

I knew I'd get some sense here - I was beginning to doubt my own sanity!

As he was referring to an office suite I did argue with him that he needed to install a 13 amp fused spur before adding the daisy chained socket outlets (which would make sense due to the relatively low wattage appliances in use) but he swore blind that within a room spurs off spurs was acceptable!

It seems he may require a little more time reading the Regs.

Thanks again.

[Dave Plowman]

It's still sometimes called Pyro by the few left who know how to use it. But more commonly MICC. Where does the MIMS come from?

I recently wanted 'bare' 2L1 to run across an exposed wood beam - it's by far the neatest way of doing it. Think I had to visit a dozen wholesalers to get the bits needed - the most difficult being the bare copper clips.

[Ed Sirett]

It's my _guess_ that what he is calling a 'spur' is not a spur of a main final circuit but simply a 'branch' on a 16A or 20A radial final socket circuit. A reasonable loading for such a final circuit would be one office room up to around 20m2

Also (IME) whilst rings are ubiquitous in domestic wiring, non-domestic wiring tends to favour radial (I guess that's customary rather than regulatory thing).

[Andrew Gabriel]

My past and current employers do this too. In practice, personal equipment is probably such a tiny proportion of the total it's not worth trying to avoid it.

Government has apparently been pointing out to companies that where they expect equipment to be used at home for work purposes, they are equally responsible for ensuring that is checked for safety. This isn't just electrical safety, it's everything that they would normally be required to check in the office, such as compliance with display screen equipment regs, etc.

[Owain]

"Dave Plowman" wrote | But more commonly MICC. Where does the MIMS come from?

Mineral Insulated Metal Sheath ?

Mineral Insulated Copper Covered (or Clad) - MICC Mineral Insulated Copper Sheath - MICS Owain

[Sparks]

How about a fused spur, off a fused spur?

For example..

Cable from back of a socket on a ring main -> a 13A fused spur

Off this spur, another spur (maybe with a lower fuse for something - is this acceptable?

I however think the below would not be acceptable...

When we had an alarm fitted at my workplace, the alarm company (Spy Alarms) did the following

Wire from back of a socket on a ring main into spur Spur then feeds alarm panel (5A fuse in spur and alarm panel) Another wire from the back of the spur (not the fuse protected side) to another spur feeding a swipe card system.

I thought this was wrong, but I stand to be corrected here!

Sparks...

[Dave Plowman]

Right. I've a feeling I've seen this stuff with an aluminium outer. Am I mistaken?

[Mike Tomlinson]

In article , Huge writes

I came back from an extended lunch [1] at work once to find the server had been unplugged and PAT tested. Without shutting it down.

The resultant fsck -y took hours.

[1] alright, I was in the pub.

[Mike Tomlinson]

In article , Dave Plowman writes

How do you run it nice and straight? (This question is from someone who has difficulty in getting clipped T&E runs looking neat.)