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 If I have got sufficiently out of date to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.
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
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.
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.
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.....
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 :-))
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.
"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
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
It seems he may require a little more time reading the Regs.
On Sat, 03 Jan 2004 14:32:02 +0000, Doctor D. wrote:
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).
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
I believe this requirement (if it ever existed) has been replaced by the
requirement to ensure that the probable load on the ring is reasonably
balanced around its perimeter. You are not allowed to have the dishwasher,
washing machine and tumble dryer sockets as the first three before it snakes
around the house.
However, you are allowed as many unfused spurs as you like, provided they
aren't all at one end and, therefore, likely to unbalance the circuit. You
can make a ring circuit will all spurs if you like. Such a circuit is quite
useful if you have concrete floors as you can run a single drop cable to
each socket from the ring in the floor above.
On Sat, 3 Jan 2004 00:39:33 -0000, Chris Oates wrote:
Depends how you define "ring". The very general local layout of the
11kV distribution round here is:
33kV SS --NC-------------NO--+
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.
Dave. pam is missing e-mail
"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.
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.
*Hang in there, retirement is only thirty years away! *
Dave Plowman email@example.com London SW 12
"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
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