"Changing a consumer unit" this time:

http://wiki.diyfaq.org.uk/index.php?..._consumer_unit

Feel free to post corrections here or on the articles discussion page,
or make them yourself.

Any obvious bits missing, unclear or misleading?

Should more or less detail be included in the live working section?

I feel there ought to be more words on dealing with a substandard TN-S
earth provision (i.e. skinny bit of uninsulated rusty wire connection
incoming cable sheath to old fusebox etc). Thoughts?

Any pictures needed?



--
Cheers,

John.

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

"John Rumm" wrote in message
...
"Changing a consumer unit" this time:

http://wiki.diyfaq.org.uk/index.php?..._consumer_unit

Feel free to post corrections here or on the articles discussion page, or
make them yourself.

Any obvious bits missing, unclear or misleading?

Should more or less detail be included in the live working section?

I feel there ought to be more words on dealing with a substandard TN-S
earth provision (i.e. skinny bit of uninsulated rusty wire connection
incoming cable sheath to old fusebox etc). Thoughts?

Any pictures needed?


Hi John,

I would propose another reason to change:
- To rationalize or simplify an existing existing which is complex (either
just to reclaim space, or to make use of the system less prone to errors).

Under Planning-Split Load Vs Multiple, it wasn't clear to me from the text
why you can get away without a time delayed RCD in a TT system if you have
multiple CUs. I think you mean this is because both CUs are to be wired in
parallel with each other, so one can have the 100mA RCD and the other a
30mA, and because they're in parallel the 100mA isn't behind (or in front of
depending on your view!) the 30mA. I think this could use clarification.

Under Starting Work-?Disconnecting the power, I thought there were cases
where is was legal to pull the main supply fuse - for example to avoid (or
put out) an electrical fire. In any case I think this could use a statement
that you can ask the supplier for permission which they should grant
(although perhaps for a fee), and may even come out and reinstall the seal.
Perhaps also a suggestion that now might be a good time to try and persuade
the supplier to come out and install a breaker for you (using mutterings
about safety to try and get a freebie).

Your link to VIR rubber cable link in Removing the Old CU is broken.

In Installing new CU-Prepare the new CU, your cable_crimping link is broken
(an extraneous _crimped I think).

Finally, I wonder if the various sections that refer (sometimes implicitly)
to extending circuit lengths shouild note that voltage drop may need to be
consider.

Cheers,
Piers

On Thu, 27 Mar 2008 00:56:47 +0000, John Rumm wrote:

"Changing a consumer unit" this time:

http://wiki.diyfaq.org.uk/index.php?..._consumer_unit

Feel free to post corrections here or on the articles discussion page,
or make them yourself.

Any obvious bits missing, unclear or misleading?

Should more or less detail be included in the live working section?

I feel there ought to be more words on dealing with a substandard TN-S
earth provision (i.e. skinny bit of uninsulated rusty wire connection
incoming cable sheath to old fusebox etc). Thoughts?

You don't mention testing the RCD(s) after installation (and making
sure your punters are out of the way when doing live testing before you've
proved your safety devices are OK!) Maybe you need to put in your
prerequisites that one should have the various bits of test kit (or a
multifunction tester) to do the job.

In general I might suggest that anyone contemplating changing a CU might
consider doing it according to the 17th ed (though I couldn't tell you off
the top of my head all the implications of that)

--
John Stumbles

The clairvoyants' meeting has been cancelled due to unforseen circumstances.

On Thu, 27 Mar 2008 00:56:47 +0000, John Rumm wrote:

"Changing a consumer unit" this time:

http://wiki.diyfaq.org.uk/index.php?..._consumer_unit

Feel free to post corrections here or on the articles discussion page,
or make them yourself.

Any obvious bits missing, unclear or misleading?

Should more or less detail be included in the live working section?

I feel there ought to be more words on dealing with a substandard TN-S
earth provision (i.e. skinny bit of uninsulated rusty wire connection
incoming cable sheath to old fusebox etc). Thoughts?

Any pictures needed?

It would be lovely, but it probably bring the diy writing from hobby
status up to 'job' status.


Comments: Really helpful. Well done.

Suggestions:Are the tails meant to be 25mm² even if the suppliers fuse is
less tan 100A? If the tails are in the meter then probably you will need
to use those ones anyway. Although if they are very old breaking the
meter seal to upgrade the tails is the lesser "crime".

There is no mention of the legal/regulatory aspect. We all hate the Prat
P, but I think it could do with a mention. Obviously some people are into
compliance paperwork etc.etc.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Ed Sirett wrote:

Any pictures needed?

It would be lovely, but it probably bring the diy writing from hobby
status up to 'job' status.

Not too much of a job since I am aware of some CU upgrading work that
needs doing shortly somewhere or other ;-)

Comments: Really helpful. Well done.

Ta

Suggestions:Are the tails meant to be 25mm² even if the suppliers fuse is
less tan 100A?

It was my understanding that they can be less than 25mm^2 with lower
capacity supplies, although obviously there is no harm is using more
than the minimum especially as it allows for a future upgrade to the
service without incurring extra work.

If the tails are in the meter then probably you will need
to use those ones anyway. Although if they are very old breaking the
meter seal to upgrade the tails is the lesser "crime".

yup

There is no mention of the legal/regulatory aspect. We all hate the Prat
P, but I think it could do with a mention. Obviously some people are into
compliance paperwork etc.etc.

Well it gets a mention as the very first bit of the article, in a boxed
out section ;-) how much more did you want?

There did not seem to be much point in describing how the building
notice procedure is supposed to work since each of the LAs seem to make
up their own rules.



--
Cheers,

John.

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

Piers Finlayson wrote:

I would propose another reason to change:
- To rationalize or simplify an existing existing which is complex (either
just to reclaim space, or to make use of the system less prone to errors).

Yes, good point frequently the case in real life.

Under Planning-Split Load Vs Multiple, it wasn't clear to me from the text
why you can get away without a time delayed RCD in a TT system if you have
multiple CUs. I think you mean this is because both CUs are to be wired in
parallel with each other, so one can have the 100mA RCD and the other a
30mA, and because they're in parallel the 100mA isn't behind (or in front of
depending on your view!) the 30mA. I think this could use clarification.

Yup, that is what I was trying to say ;-)

(having said that, now TLC stock time delayed RCDs a sensible price it
is less of an issue!)

Under Starting Work-?Disconnecting the power, I thought there were cases
where is was legal to pull the main supply fuse - for example to avoid (or
put out) an electrical fire. In any case I think this could use a statement
that you can ask the supplier for permission which they should grant
(although perhaps for a fee), and may even come out and reinstall the seal.
Perhaps also a suggestion that now might be a good time to try and persuade
the supplier to come out and install a breaker for you (using mutterings
about safety to try and get a freebie).

Yes there are procedures to have then disconnect and reconnect
officially. I presume they will want to see signed off papers showing
that the installation passed testing prior to reconnecting.

Your link to VIR rubber cable link in Removing the Old CU is broken.

In Installing new CU-Prepare the new CU, your cable_crimping link is broken
(an extraneous _crimped I think).

ta, will fix.


Finally, I wonder if the various sections that refer (sometimes implicitly)
to extending circuit lengths shouild note that voltage drop may need to be
consider.

Possibly, although you would need to have a very marginal design in the
first place... I suppose you could move the CU by 4m without need for
additional protection for the tails.



--
Cheers,

John.

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

is the big master on/off switch you mention
the same as an isolator switch?

I cant find one at Wickes or Screwfix of CPC,
but think I should get one for my house
before I do much more electrical repairs...

is this the kind of isolator for a house?

http://www.tlc-direct.co.uk/Main_Ind...EM_Islolators/



"George (dicegeorge)" wrote in message
...
is the big master on/off switch you mention
the same as an isolator switch?

I cant find one at Wickes or Screwfix of CPC,
but think I should get one for my house
before I do much more electrical repairs...

On Thu, 27 Mar 2008 22:37:40 +0000, John Rumm wrote:

(having said that, now TLC stock time delayed RCDs a sensible price it
is less of an issue!)

Since when? About mid-Feb I looked and they only had 'normal' 100mA RCDs.
Ended up getting a TD unit from Harbro(?) for about 70 notes.

--
John Stumbles

The clairvoyants' meeting has been cancelled due to unforseen circumstances.

John Rumm wrote:

Yes there are procedures to have then disconnect and reconnect
officially.

A link to http://2008.energynetworks.org/tempo...isconnections/ would
be useful here, also a reference to the fact that some suppliers will
provide an isolator, allowing ... [etc.]

--
Andy

John Stumbles wrote:
On Thu, 27 Mar 2008 22:37:40 +0000, John Rumm wrote:

(having said that, now TLC stock time delayed RCDs a sensible price it
is less of an issue!)

Since when? About mid-Feb I looked and they only had 'normal' 100mA RCDs.
Ended up getting a TD unit from Harbro(?) for about 70 notes.

Down the bottom of the list...

http://www.tlc-direct.co.uk/Main_Ind...CDs/index.html

(£40 less than what RS charge for the 6400S)

--
Cheers,

John.

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

George (dicegeorge) wrote:
is this the kind of isolator for a house?

http://www.tlc-direct.co.uk/Main_Ind...EM_Islolators/

That's a three phase and neutral isolator - so a bit OTT for domestic
use in most cases.

A bog standard two pole switch as used for the incomer of a CU:

http://www.tlc-direct.co.uk/Main_Ind...tch/index.html

in a two module enclosure would be adequate.


--
Cheers,

John.

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