Difference and use of Part P and 17th edition.

[EddieJT]

Forgive my ignorance as I am brand new to house electrics, and so am doing as much reading up as I can before I move into my new house, and and consider tackling the wiring.

So apologies for any seemingly stupid questions.

I understand a DIYer is now legally obliged to follow regs in accordance with Part P and/or 17th edition? But what is the difference between the 2, and how are they used?

An idiots guide would be much appreciated.

 

[Steve]

The 17th edition, 2008 is the new updated version of the wiring regs and has made quite "expensive" changes to the way electricians now have to wire properties, on a practical level. The wiring regulations are a British standard, but do not form any sort of lawful document.

Part P, 2005, sets out rules that state who can do electrical work in DOMESTIC properties, and under what circumstances. It also states that the work must be done to a good standard, one way to prove this is to comply with, and work to the 17th edition. Part P is the law, non-compliance is an offense.

As a competent DIYer, under part P, you must notify your work to the relevant building control department and pay their fee for inspection and testing. As an example, Doncaster council charges ~£100 for minor work and ~£300 for rewires.

 

[bongos]

In a dwelling, certain electrical work must be notified to your LABC. Some work does not have to be notified.

However it must all comply with Part P, whether notifiable or not.

For a list of notifibale work see here or look in the wiki for more info.

 

[securespark]

"expensive" changes

Or expansive changes?

Or both?

 

[Steve]

expensive - RCBOs or metal conduit.

 

[ericmark]

I will not repeat the above but I will point out Part P click here for Government Page is not the only building regulation. You will see a load of others Part L tells us what bulbs we can use and Part M the heights of sockets on the wall. Part F tells us size of fan in kitchens and bathrooms etc.
The Part documents are however in layman's English not found Welsh edition yet. But the 17th Edition also called BS7671:2008 is not in layman's English and it takes some interpretation. Electricians on sites like this often debate it's meaning. Also it is not only to do with houses it also takes in most commercial premises so has to be worded so as to take account of both. So it will not say you must use two RCD's for example in a house but says "take account of danger that may arise from the failure of a single circuit such as a lighting circuit" and "reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor currents produced
by equipment in normal operation". We as electricians know that means we can't use a single 30ma RCD on a Domestic premises.
The guides to the 17th Edition do explain a little more in layman's terms but are still not easy reading.
The problem today is rule of thumb is dyeing and more and more we need expensive meters and calculations to work out what we can do within the regulations.
If you read through these pages you will see how people have not measured first and then found the ring main is too big.
In theory you should be able to look up the installation certificates that came with the house and read off all the reading and calculate what extra can be added but in practice often there are no installation certificates and if there are then I would not really trust the readings given.
Without £750 worth of test gear it is all too easy to add to your wiring only to be told by council it has failed.

 

[hairyben]

Without £750 worth of test gear it is all too easy to add to your wiring only to be told by council it has failed.

Basic circuit checking can be done with a £20 multimeter. It won't give you certifiable readings, but in such an example of a DIYer carrying out pre-certification checks it should suffice.

 

[ericmark]

If one is well within the limits then I will agree the multimeter may well do the job but reading 1.25 ohms on a multimeter even with my AVO Mk8 is to say the least a little hit and miss. And problem is when it is tested on completion if it fails what then

 

[ban-all-sheds]

Forgive my ignorance as I am brand new to house electrics, and so am doing as much reading up as I can before I move into my new house, and and consider tackling the wiring.

//www.diynot.com/forums/viewtopic.php?p=75416#75416

I understand a DIYer is now legally obliged to follow regs in accordance with Part P and/or 17th edition? But what is the difference between the 2, and how are they used?

//www.diynot.com/wiki/electrics:part-p

 

[ban-all-sheds]

I will not repeat the above but I will point out Part P click here for Government Page

Note that's a link to Approved Document P, not to Part P of the Building Regulations.

Part L tells us what bulbs we can use

No it doesn't - Part L says:

L1 Reasonable provision shall be made for the
conservation of fuel and power in buildings
by─
(a) limiting heat gains and losses─
(i) through thermal elements and
other parts of the building fabric;
and
(ii) from pipes, ducts and vessels used
for space heating, space cooling
and hot water services;
(b) providing and commissioning energy
efficient fixed building services with
effective controls; and
(c) providing to the owner sufficient
information about the building, the
fixed building services and their
maintenance requirements so that the
building can be operated in such a
manner as to use no more fuel and
power than is reasonable in the
circumstances.

and Part M the heights of sockets on the wall.

No it doesn't - Part M says (regarding dwellings):

M1 Reasonable provision shall be made for
people to—
(a) gain access to; and
(b) use the building and its facilities

M4 (1) Reasonable provision shall be made in
the entrance storey for sanitary conveniences,
or where the entrance storey contains no
habitable rooms, reasonable provision for
sanitary conveniences shall be made in either
the entrance storey or principal storey.
(2) In this paragraph “entrance storey” means
the storey which contains the principal entrance
and “principal storey” means the storey nearest
to the entrance storey which contains a
habitable room, or if there are two such storeys
equally near, either such storey.

but that the requirements of Part M do not apply to—
(a) an extension of or material alteration
of a dwelling; or
(b) any part of a building which is used
solely to enable the building or any
service or fitting in the building to be
inspected, repaired or maintained.

Part F tells us size of fan in kitchens and bathrooms etc.

No it doesn't - Part F says:

F1 There shall be adequate means of ventilation
provided for people in the building.

 

[ban-all-sheds]

I will not repeat the above but I will point out Part P click here for Government Page

Note that's a link to Approved Document P, not to Part P of the Building Regulations.

Part L tells us what bulbs we can use

No it doesn't - Part L says:

L1 Reasonable provision shall be made for the
conservation of fuel and power in buildings
by─
(a) limiting heat gains and losses─
(i) through thermal elements and
other parts of the building fabric;
and
(ii) from pipes, ducts and vessels used
for space heating, space cooling
and hot water services;
(b) providing and commissioning energy
efficient fixed building services with
effective controls; and
(c) providing to the owner sufficient
information about the building, the
fixed building services and their
maintenance requirements so that the
building can be operated in such a
manner as to use no more fuel and
power than is reasonable in the
circumstances.

and Part M the heights of sockets on the wall.

No it doesn't - Part M says (regarding dwellings):

M1 Reasonable provision shall be made for
people to—
(a) gain access to; and
(b) use the building and its facilities

M4 (1) Reasonable provision shall be made in
the entrance storey for sanitary conveniences,
or where the entrance storey contains no
habitable rooms, reasonable provision for
sanitary conveniences shall be made in either
the entrance storey or principal storey.
(2) In this paragraph “entrance storey” means
the storey which contains the principal entrance
and “principal storey” means the storey nearest
to the entrance storey which contains a
habitable room, or if there are two such storeys
equally near, either such storey.

but that the requirements of Part M do not apply to—
(a) an extension of or material alteration
of a dwelling; or
(b) any part of a building which is used
solely to enable the building or any
service or fitting in the building to be
inspected, repaired or maintained.

Part F tells us size of fan in kitchens and bathrooms etc.

No it doesn't - Part F says:

F1 There shall be adequate means of ventilation
provided for people in the building.

 

[ColJack]

wanted to make sure he got the point BAS?

 

[EddieJT]

Great info. Thanks guys.

I'm sure I'll have many questions over the next few weeks. Be warned.

 

[EddieJT]

Forgive my ignorance as I am brand new to house electrics, and so am doing as much reading up as I can before I move into my new house, and and consider tackling the wiring.

//www.diynot.com/forums/viewtopic.php?p=75416#75416

Good link!

 

[maltaron]

Ericmark said "only to be told by the council that it has failed". I seem to remember a post in this forum a short while ago that stated "only one Council in the whole country has an inspector capable of checking compliance with 17th ed"