It just seems bizarre that the minimum numbers required are so brazenly published in the OSG when there isn't a correlation to BS7671 which can be applied. 

I'm not so sure it's illogical. BS 7671 gives the fundamental requirements (as many sockets as necessary and in suitable positions) whereas the OSG (like building regs approved documents) gives suggestions on how that might be achieved in some common circumstances given typical usage. BS 7671 can't just say you should always have 'n' sockets in a particular type of room - there are just too many variables from size of room (50m² bedroom in a royal palace vs a 4m² "box room" bedroom never mind how it's actually used. Such tables just give a useful starting point - if that's what might satisfy the requirement in a typical semi, how would I scale that up/down to meet these particular circumstances sort of thing.

Interestingly the US regs seem to take a more prescriptive approach - starting from pretty much the same starting point as us (as many sockets as necessary and in suitable positions), they then interpret that as you should be able to put an appliance with a 6' lead anywhere you like around the perimeter of a room without the lead crossing a doorway - hence a requirement for a socket within 6' of each side of a doorway and not more than 12' between sockets elsewhere. That sort of thing can end up with having to put sockets in awkward places that on-one's ever going to use though.

  - Andy.

I agree Andy, the OSG is just a guide - some people like the guidance it provides ... seems in this instance it's causing confusion because of periodic inspection & test.

Having said that, most of the information regarding inspection and testing is guidance ... which really is where things need to be so that competent inspectors can make judgements based on the particular circumstances ?

I get what you're saying, but to me it does seem illogical why the OSG and BS7671 aren't signing from the same hymn sheet. Maybe BS7671 aren't saying 'you must have n sockets in a particular room', though the OSG is saying exactly that, as are the LA (based on Electrical Safety First). It makes a mockery of an EICR when we can state an installation is compliant with the current edition of BS7671 when it's so easy for people to pull it apart afterwards with conflicting versions of what is acceptable. If it's important enough to be stated in the OSG (and force landlords to do something about it via a 'Hazard Awareness Notice' from the LA) then why isn't it made clearer in BS7671 so we can code it appropriately? 

It isn't rocket science in my view for the OSG and BS7671 to be in lockstep regarding what they separately state. Isn't that what they try to do with everything else? 

Scott Seedell said:

It makes a mockery of an EICR when we can state an installation is compliant with the current edition of BS7671 when it's so easy for people to pull it apart afterwards with conflicting versions of what is acceptable.

Or you could take the view that, if there is no evidence a smaller number of socket-outlets is unsafe for a particular homeowner, the installation is suitable for continued service in that instance. In another property, or in rented accommodation, you might see evidence of things being unsafe, and make a different decision. As an example, if you were carrying out an EICR on "change of occupancy", the new owner might welcome the lack of outlets being reported ... it could be an issue for them even if not for the previous occupants.

I'm not sure that providing concrete "fixed and firm rules" for inspection and testing is a good idea ... but then again, other people might want a "computer says no" approach taken in the industry ?

gkenyon said:

Or you could take the view that, if there is no evidence a smaller number of socket-outlets is unsafe for a particular homeowner, the installation is suitable for continued service in that instance. In another property, or in rented accommodation, you might see evidence of things being unsafe, and make a different decision. As an example, if you were carrying out an EICR on "change of occupancy", the new owner might welcome the lack of outlets being reported ... it could be an issue for them even if not for the previous occupants.

Indeed, and that's exactly what we did say in that instance. However, going back to my original question, where does it put us as testers if the installation is suitable for continued use but there are insufficient numbers? Is it worthy of a C3 (even if just to state we have recognised it doesn't satisfy OSG and LA requirements) and if so, under which regulation of BS7671? 

gkenyon said:

Or you could take the view that, if there is no evidence a smaller number of socket-outlets is unsafe for a particular homeowner, the installation is suitable for continued service in that instance. In another property, or in rented accommodation, you might see evidence of things being unsafe, and make a different decision. As an example, if you were carrying out an EICR on "change of occupancy", the new owner might welcome the lack of outlets being reported ... it could be an issue for them even if not for the previous occupants.

Indeed, and that's exactly what we did say in that instance. However, going back to my original question, where does it put us as testers if the installation is suitable for continued use but there are insufficient numbers? Is it worthy of a C3 (even if just to state we have recognised it doesn't satisfy OSG and LA requirements) and if so, under which regulation of BS7671? 

Scott Seedell said:

Is it worthy of a C3 (even if just to state we have recognised it doesn't satisfy OSG and LA requirements) and if so, under which regulation of BS7671?

Well, the C3 itself is only guidance, because it's only mentioned in Appendix 6 of BS 7671, which is 'informative'.

If you want something for Insufficient or poorly placed socket-outlets: Regulation 132.3 in general, with a view to list item (i) ?

(The design was suitable at some point in the past, but for modern domestic usage, perhaps not now?)

I would say that this requires a little more explanation from the inspector than just saying "insufficient socket-outlets, 132.3, C3" ... some explanation for the decision is really needed I think.

AJJewsbury said:

From a BS 7671 perspective it's not just about numbers - you could have 20 double sockets in a room, but if they were all grouped together at one end you could still be in a position of not having a reasonably convenient socket at the other end. If it's a problem in there not being a socket where it's needed then quote 553.1.7.

   - Andy.

Also what Andy said. In reality, 553.1.7 supports 132.3.