Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.

"Woland" wrote in message
...
Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.


Hi
I would put a radial circuit in. That way you only have to isolate that
circuit, if you have to work on it. Also if it does go down your whole house
does not.

Ring rinals are on their way out.
I know this because I am at Leeds College of Technology, I am studying for
Level 3. We covered this very subject today.
I am about to rewire my home and am putting in radial circuits in every
room.


Kind Regards.


Micky Savage.

P.S. Testing is also a lot quicker on Radial circuits, so you won't have to
pay the sparky as much for your testing.

On Sep 18, 5:54*pm, "Micky Savage" wrote:
"Woland" wrote in message

...



Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.

Hi
I would put a radial circuit in. That way you only have to isolate that
circuit, if you have to work on it. Also if it does go down your whole house

It is already radial in the sense that there is one armoured cable
from the 40A electronic fuse in the home CU to the summer house, so
the total load should not exceed 40A x 240V.

It's just inside the summer house that I would place another CU on
the receiving end of the armoured cable and create a local ring, the
idea being that either the summer house CU electronic fuses deal with
overloads/spikes/ whatever or in the worst case the 40A fuse in the
house Cu deals with it.

W.

On Sep 18, 5:54*pm, "Micky Savage" wrote:
"Woland" wrote in message

...



Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.

Hi
I would put a radial circuit in. That way you only have to isolate that
circuit, if you have to work on it. Also if it does go down your whole house
does not.

Ring rinals are on their way out.
I know this because I am at Leeds College of Technology, I am studying for
Level 3. We covered this very subject today.
I am about to rewire my home and am putting in radial circuits in every
room.

Kind Regards.

Micky Savage.

P.S. Testing is also a lot quicker on Radial circuits, so you won't have to
pay the sparky as much for your testing.

Funny, considering the ring circuit has such safety advantages
http://www.wiki.diyfaq.org.uk/index....e=Ring_circuit


NT

wrote in message
...
On Sep 18, 5:54 pm, "Micky Savage" wrote:
"Woland" wrote in message

...



Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.

Hi
I would put a radial circuit in. That way you only have to isolate that
circuit, if you have to work on it. Also if it does go down your whole
house
does not.

Ring rinals are on their way out.
I know this because I am at Leeds College of Technology, I am studying for
Level 3. We covered this very subject today.
I am about to rewire my home and am putting in radial circuits in every
room.

Kind Regards.

Micky Savage.

P.S. Testing is also a lot quicker on Radial circuits, so you won't have
to
pay the sparky as much for your testing.

Funny, considering the ring circuit has such safety advantages
http://www.wiki.diyfaq.org.uk/index....e=Ring_circuit


NT


No not funny it's going to be fact.

Micky.

Micky Savage coughed up some electrons that declared:


wrote in message
...
On Sep 18, 5:54 pm, "Micky Savage" wrote:
"Woland" wrote in message

...



Dear all,

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?) or similar (seems like citing some obscure Criminal
Law Act though...).

Now the problem: in 2000 I had my electrical system partially rewired
and 'updated' to the current regulations of the times (Scotland).
A CU with no RCD for light and power in the house, plus another CU
with RCD (there were no split units at the time).

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

I originally asked some supposed sparkies and the majority seemed to
conclude that I could manage the work myself as it were a 'shed-like
outhouse' but I', mot this very much convinced of that. If that's not
the case I would still do the job myself according to current
regulations and than waste a bit of money on the usual (un)qualified
guy to let him fill a certificate of compliance/whatever.

Now...

1) I read somewhere (now well buried in one of the posts) that I'd
better link the armoured cable, at the house to the non-RCD CU and
then provide a split unit at the summer house end rather than keeping
the current setup.

2) Anything else to comply with these apparently frightening
regulations? (I would create ring circuits inside the summer house,
have a RCD-protected and a non-RCD protected split unit if possible,
etc). Note that I would use the summer house for woodworking involving
a range of professional power tools

Thanks

E.

Hi
I would put a radial circuit in. That way you only have to isolate that
circuit, if you have to work on it. Also if it does go down your whole
house
does not.

Ring rinals are on their way out.
I know this because I am at Leeds College of Technology, I am studying
for Level 3. We covered this very subject today.
I am about to rewire my home and am putting in radial circuits in every
room.

Kind Regards.

Micky Savage.

P.S. Testing is also a lot quicker on Radial circuits, so you won't have
to
pay the sparky as much for your testing.

Funny, considering the ring circuit has such safety advantages
http://www.wiki.diyfaq.org.uk/index....e=Ring_circuit


NT


No not funny it's going to be fact.

Micky.

Lecturers sometimes have their own slant on things and it may or may not
align with reality :-

OK - rather than just state what I think, lets have some fun instead...

I would like to postulate that 32A final socket circuits are good for many
applications because they doesn't keel over when you plug two 3kW
appliances in. If you disagree, the debate is dead, if agree, please go to
next step:

Next step: Can you construct a 32A radial circuit using 13A sockets?

Cheers

Tim

Tim S wrote:

Lecturers sometimes have their own slant on things and it may or may not
align with reality :-

Quite. AFAIK there's no intention whatever to abandon the faithful ring
circuit, but there is something of a campaign going on to educate
electricians about the radial alternatives. Hence Appendix 15 in the
New Red Book.

Next step: Can you construct a 32A radial circuit using 13A sockets?

Yes, of course - it's one of the standard circuits: 4 mm^2 cable for the
main circuit, spurs in 2.5 subject to the same rules as for rings,
max. floor area served 75 m^2.

--
Andy

Micky Savage wrote:

P.S. Testing is also a lot quicker on Radial circuits, so you won't have
to
pay the sparky as much for your testing.

Funny, considering the ring circuit has such safety advantages
http://www.wiki.diyfaq.org.uk/index....e=Ring_circuit


NT


No not funny it's going to be fact.

Well leaving aside any issues of why you would be paying anyone else to
test your circuits for you, one needs to consider the circumstance.

If you have just installed a new ring final circuit, then it is no more
difficult or time consuming to test than a radial. The time that a ring
circuit becomes more difficult to test is when you are attempting to
discover and reverse engineer its topology after a period alterations etc.

IME the general fault tolerance in real world situations is better with
rings than radials since the most typical faults have a lesser impact:

http://www.wiki.diyfaq.org.uk/index...._circuit_types



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Woland wrote:

I have veen following anxiously the issue of electrical regulations,
XVII ed. (part P?)

The 17th edition and Part P are quire separate things. The latter
doesn't apply in Scotland.

Now the problem: in 2000 [...] (there were no split units at the time).

Oh yes there were.

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

With that length of run the effective current rating of your submain
will be limited by voltage drop and not by the current rating of the cable.

You might find
http://wiki.diyfaq.org.uk/index.php?...ricity_outside
useful.

--
Andy

Now the problem: in 2000 [...] *(there were no split units at the time).

Oh yes there were.

Was just a hypothesis

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

With that length of run the effective current rating of your submain
will be limited by voltage drop and not by the current rating of the cable.

You might findhttp://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside
useful.

I had read that and I was expecting a serious voltage drop (no load
reading doesn't count, obviously).
So I set up the usual easy measurement with a 2 KW load (circular saw
+ lights + other resistive loads) and... strange but true no drop!

Experiment repeated several time... same result. I am actually curious
to find out why I'm not withnessing any voltage drop... maybe the load
is too small?

W.
--
Andy

"Woland" wrote in message
...
Now the problem: in 2000 [...] (there were no split units at the time).

Oh yes there were.

Was just a hypothesis

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

With that length of run the effective current rating of your submain
will be limited by voltage drop and not by the current rating of the
cable.

You might
findhttp://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside
useful.

I had read that and I was expecting a serious voltage drop (no load
reading doesn't count, obviously).
So I set up the usual easy measurement with a 2 KW load (circular saw
+ lights + other resistive loads) and... strange but true no drop!

Experiment repeated several time... same result. I am actually curious
to find out why I'm not withnessing any voltage drop... maybe the load
is too small?

You're obviously using special zero-ohm oxygen-free speaker cable.
Supplier/price?

Woland wrote:

I had read that and I was expecting a serious voltage drop (no load
reading doesn't count, obviously).
So I set up the usual easy measurement with a 2 KW load (circular saw
+ lights + other resistive loads) and... strange but true no drop!

A saw's not much good as a test load because the current drawn will vary
wildly with the mechanical load. Use a 3 kW fan heater or similar.

Experiment repeated several time... same result. I am actually curious
to find out why I'm not withnessing any voltage drop... maybe the load
is too small?

How are you measuring? Is the cable perhaps bigger than you think?

The resistance of a 40 m run of 2.5 2-core will be about 0.6 ohm. If
you were to allocate the whole 3% permitted drop (for lighting) to the
submain on the assumption that there'll be little more in the short
wiring in the summerhouse, the max load will be 6.9 V / 0.6 ohm which is
only 11.5 amps.

What equipment do you propose to use in the summerhouse? For a 32 A
supply you really need a 10 mm^2 cable, or 6 mm^2 (4 at a pinch) for a
16 A feed.

--
Andy

On Sep 19, 12:11*am, Woland wrote:
Now the problem: in 2000 [...] *(there were no split units at the time).

Oh yes there were.

Was just a hypothesis

A 49Amp MAX armoured cable (should be 2.5mm^2, not certain but I'm
certain it's 49 Amp MAX) which is some 40 metres long goes from the
RCD-protected CU straight into the summer house to provide power.

With that length of run the effective current rating of your submain
will be limited by voltage drop and not by the current rating of the cable.

You might findhttp://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside
useful.

*I had read that and I was expecting a serious voltage drop (no load
reading doesn't count, obviously).
So I set up the usual easy measurement with a 2 KW load (circular saw
+ lights + other resistive loads) and... strange but true no drop!

Experiment repeated several time... same result. I am actually curious
to find out why I'm not withnessing any voltage drop... maybe the load
is too small?

W.

Begs the question of how you're measuring it. Basic physics tells us
there will be a v drop.


NT

Begs the question of how you're measuring it. Basic physics tells us
there will be a v drop.

No it doesn't. The OP is not indulging in petitio principii. It might
raise the question, but it doesn't beg it.

And to sound off on ring circuits vis-a-vis radials: weren't rings in
part devised to cope with post-WW2 copper shortages - wouldn't it be
'greener' to continue using rings as radial usage would increase
copper usage.

And another thing...with all the campaigning to minimise the use of
'standby' rather than physically 'off' switches, and encourage people
to unplug mobile phone chargers and the suchlike when not in use,
won't the requirements for RCDs significantly increase base-load power
consumption? All the RCDs I've come across dissipate a few watts.
Replacing all the rewireable fuses in my consumer unit with RCBOs; or
indeed replacing sockets with ones that have RCD protection build in
will increase consumption.

Regards,

Sid

wrote:

And to sound off on ring circuits vis-a-vis radials: weren't rings in
part devised to cope with post-WW2 copper shortages - wouldn't it be

They were... although

'greener' to continue using rings as radial usage would increase
copper usage.

Prolly better to use whichever is most appropriate for the particular
circumstances. Depending on layout a ring might use more copper than a
4mm^2 radial anyway.

And another thing...with all the campaigning to minimise the use of
'standby' rather than physically 'off' switches, and encourage people
to unplug mobile phone chargers and the suchlike when not in use,
won't the requirements for RCDs significantly increase base-load power
consumption? All the RCDs I've come across dissipate a few watts.
Replacing all the rewireable fuses in my consumer unit with RCBOs; or
indeed replacing sockets with ones that have RCD protection build in
will increase consumption.

Can't say I have ever noticed a RCD getting warm, but then again I have
never measured their power consumption. Either way, you can't expect
joined up thinking from the government can you?

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/