What happens in a Part P Inspection?

[tcs200]

Hello all,

I am having a Part P inspection of a new ring main and new lighting circuit carried out towards the end of next week.

Because I now have the lucky task of finishing the decoration of the property myself, and some time on my hands before the inspection, I wanted to find out want the inspector will need to see.

In fact, I have a number of specific questions:

The wiring is in PVC conduit chased into the walls - can I plaster over these before inspection?

Some connections are made with junction boxes in floor spaces. Can I replace the floorboards before the inspection, or do these need to be visible too?

Should all the sockets/switches be a) fully screwed down, b) screws inserted but left loose for visual inspection or c) left at the full extent of the wiring for inspection?

Thanks in advance for any advice.

Tom

 

[sm1thson]

the part p malarkey is still in its infancy and varies council to council in how and what they do. from what i have seen building control are there to help so its probably best asking them direct.

as for the junction boxes this has allways looked a grey area to me, i dont like them and they have to be in an accesible place, many say that under the floor is not acessable (especialy as the next owner may put laminate/ wood down). -would be worth either asking building control or doing it properly with Ratchet Crimping Pliers (a properly crimped and sleaved joint is classed as permiment, screwed joint needs accesing to retighten screws as they do become loose.

 

[plugwash]

btw why the hell have you got junction boxes in the floor spaces on a new installation? i can understand doing it when reworking an existing installation and limited by whats there but not in new work.

 

[Paul Barker]

a properly crimped and sleaved joint is classed as permiment, screwed joint needs accesing to retighten screws as they do become loose.

Do you mean to spur off a ring under the floor it is better to crimp? What do you sleeve with heatshrink?

Thanks

Paul

 

[Spark123]

It is better to put as many new sockets on the ring as possible, any spurs are better taken from the back of sockets which are on the ring.

 

[ellal]

a properly crimped and sleaved joint is classed as permiment, screwed joint needs accesing to retighten screws as they do become loose.

In the real world, what's the difference between a 'screwed joint' in a junction box and one in a socket? - and how many loose connections would actually be picked up without regular/periodical metering/inspections?

 

[securespark]

In the real world, what's the difference between a 'screwed joint' in a junction box and one in a socket? - and how many loose connections would actually be picked up without regular/periodical metering/inspections?

A JB under the floor is not accessible, whereas a socket generally is.

 

[ellal]

In the real world, what's the difference between a 'screwed joint' in a junction box and one in a socket? - and how many loose connections would actually be picked up without regular/periodical metering/inspections?

A JB under the floor is not accessible, whereas a socket generally is.

but how would a 'break' in either case be detected without regular inspections?..in reality!

how many people get their ring mains checked at all?

 

[dingbat]

but how would a 'break' in either case be detected without regular inspections?..in reality!

Most are found when the loose connections cause problems. This week alone I have replaced three burnt-out shower switches and a badly burned socket and removed a consumer unit with several examples of melted insulation. All of these were caused by loose terminations.

Of course, in domestic electrics 'safety second' seems to be the rule... all of the above problems came to light only because the occupants were inconvenienced, not because they were worried about safety.

how many people get their ring mains checked at all?

Practically nobody. But perhaps they should...

http://www.southwales-fire.gov.uk/SWFSCMS/OurPerformance/statistics.htm

 

[The Jeep]

Interestingly, well over 50% of all screwed connections I check are loose. I'm always tightening things up on every job I do (but not too tight).

However, I've been surprised at how little tightness is sometimes necessary to allow an electrical connection to function. For low power devices, this situation can be sustained for a longer time than a loose connection to a high-power device, such as an electric shower.

When I'm tightening up, say, a large diameter cable in a CCU, I tighten it once, then retighten it again after the metal has 'settled down'.

I guess screwed connections will loosen with time, but I get the feeling that lots of sparks haven't all developed what I call an 'engineer's feel' for how much to 'nip things up'.

 

[Taylortwocities]

There is the original tightness and there is the effect of conductors heating up and cooling down. The thermal effect causes terms to loosen over time.

TTC

 

[The Jeep]

I guess that could be right, but most connections don't (shouldn't) get that hot. Or perhaps small temperature changes can have the undesired effect?

Maybe it's time we moved beyond screwed connections? Any ideas for the Dragons' Den?

 

[HDRW]

I guess that could be right, but most connections don't (shouldn't) get that hot. Or perhaps small temperature changes can have the undesired effect?

Maybe it's time we moved beyond screwed connections? Any ideas for the Dragons' Den?

Well the Yanks use twisted connections a lot - twist the wires together and then twist one ot those ceramic cones over the top to improve the contact and insulate the join. But they also have aluminium cable, and that is much more susceptible to thermal cycling loosening things because it has a much greater thermal coefficient (expands and contracts much more for a given temperature change).

Personally I think we should stay with screws!

Cheers,

Howard

 

[The Jeep]

Personally I think we should stay with screws!

So, Howard, your message is 'keep screwing our customers' (their connections, that is )