As BS 7671 has been gradually extending its scope over the years, so we're now just about at the point that it covers any electrical installation that isn't specifically covered by another (BS?) standard (to paraphrase section 110) - and specifically mentions communication, signalling and control fixed wiring. So I'm trying to figure out what standards apply to what: A few examples: Power and lighting - yes, I'm happy that's just BS 7671. Phone cabling - comes under BS 6701 that seems clear enough (maybe in addition to BS 7671, but there's room for deviation from BS 7671 demands all the same) ELV intruder alarm wiring - I've come across BS EN 50131 series but can't tell (without paying a fortune) whether that covers just individual components or also acts as an installation standard - anyone know? Fixed speaker wiring (say from a wall or ceiling speaker to 4mm sockets/binding posts on the wall behind the hifi) UHF co-ax (i.e. TV aerial/satellite) LV control wiring for CH systems (I'm guessing this is BS 7671 although every EICR I see seems to suggest otherwise) Likewise similar wiring - e.g. pump/valves for solar thermal systems, air-con or heatpumps. ELV heating control wiring (e.g. from 12V 'network' type room 'stats to underfloor heating manifold controllers) Structured cabling (CAT 5 kind of thing) - usually done to TIA/EIA-568 - am I right in thinking that BS EN 50173 is equivalent? Anyone know of some standards that would apply to these instead of (or in addition to) BS 7671? Or on paper at least, should I be looking to find sheathed speaker cables, IP2X binding posts and a suitable 30mA RCD for when they're concealed in the wall (as far as I can tell the amplifier isn't a SELV source), intruder alarm contacts that don't rely on the timber door frame to complete the enclosure, or co-ax that complies with BS 5467, 6724, 7846, 8436 or 60702-1? ? - Andy.

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Which bits of domestic wiring does BS 7671 cover?

As BS 7671 has been gradually extending its scope over the years, so we're now just about at the point that it covers any electrical installation that isn't specifically covered by another (BS?) standard (to paraphrase section 110) - and specifically mentions communication, signalling and control fixed wiring. So I'm trying to figure out what standards apply to what:

A few examples:

Power and lighting - yes, I'm happy that's just BS 7671.

Phone cabling - comes under BS 6701 that seems clear enough (maybe in addition to BS 7671, but there's room for deviation from BS 7671 demands all the same)

ELV intruder alarm wiring - I've come across BS EN 50131 series but can't tell (without paying a fortune) whether that covers just individual components or also acts as an installation standard - anyone know?

Fixed speaker wiring (say from a wall or ceiling speaker to 4mm sockets/binding posts on the wall behind the hifi)

UHF co-ax (i.e. TV aerial/satellite)

LV control wiring for CH systems (I'm guessing this is BS 7671 although every EICR I see seems to suggest otherwise)

Likewise similar wiring - e.g. pump/valves for solar thermal systems, air-con or heatpumps.

ELV heating control wiring (e.g. from 12V 'network' type room 'stats to underfloor heating manifold controllers)

Structured cabling (CAT 5 kind of thing) - usually done to TIA/EIA-568 - am I right in thinking that BS EN 50173 is equivalent?

Anyone know of some standards that would apply to these instead of (or in addition to) BS 7671? Or on paper at least, should I be looking to find sheathed speaker cables, IP2X binding posts and a suitable 30mA RCD for when they're concealed in the wall (as far as I can tell the amplifier isn't a SELV source), intruder alarm contacts that don't rely on the timber door frame to complete the enclosure, or co-ax that complies with BS 5467, 6724, 7846, 8436 or 60702-1? ?

- Andy.

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0 AJJewsbury over 5 years ago

Thanks Graham - that's very useful.

BS 6701 reinforces or augments BS 7671 requirements. There are no "conflicts". BS 6701 actually refers to BS 7671 as a requirement.

That puzzles me - as I thought the only bi-colour allowed by BS 7671 for conductor identification was G/Y (for protective conductors) - so how does that sit with CW1308 etc cables with their bi-colour dots and backgrounds (I can't see how they comply with table 51, which seemingly 514.4.4 insists on) - indeed if you have a large enough cable pair 18 is green/yellow coded (if by dots rather than stripes) so and additional conflict with 514.4.2 there it seems. Likewise I don't think BS 7671 permits the blue core of my alarm cable to be used for anything other than "neutral". (It seems a bit in two minds over green as well.) Then as far as I can tell, an incoming BT line doesn't meet BS 7671's rather specific requirements for a SELV or PELV source (and presumably unlikely to give a ringer signal of up to 80V a.c.) let alone many mains powered answering machines etc - so seemingly I must treat it fully as FELV if I'm to comply with BS 7671 chapter 41 - so I need cables insulated according to the voltage of the 'primary circuit' (mains?) and all exposed-conductive-parts earthed? Then, as you say, there's the 30mA RCD issue where the cables are concealed in walls.

Similarly the TV, aerial amplifier, sat box etc don't obviously meet BS 7671 limited definitions of SELV/PELV sources (and several inject a d.c. voltage to power LNBs, masthead amps or remote control eyes, so we can't really presume the only power source is the aerial). Maybe it would make sense to earth the screen of co-ax cables concealed in walls rather than going down the RCD route, but none of the cable types permitted by 522.6.204 (i) are suitable for UHF.

Or have I got completely the wrong end of the stick?

- Andy.
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0 AJJewsbury over 5 years ago

Thanks Graham - that's very useful.

BS 6701 reinforces or augments BS 7671 requirements. There are no "conflicts". BS 6701 actually refers to BS 7671 as a requirement.

That puzzles me - as I thought the only bi-colour allowed by BS 7671 for conductor identification was G/Y (for protective conductors) - so how does that sit with CW1308 etc cables with their bi-colour dots and backgrounds (I can't see how they comply with table 51, which seemingly 514.4.4 insists on) - indeed if you have a large enough cable pair 18 is green/yellow coded (if by dots rather than stripes) so and additional conflict with 514.4.2 there it seems. Likewise I don't think BS 7671 permits the blue core of my alarm cable to be used for anything other than "neutral". (It seems a bit in two minds over green as well.) Then as far as I can tell, an incoming BT line doesn't meet BS 7671's rather specific requirements for a SELV or PELV source (and presumably unlikely to give a ringer signal of up to 80V a.c.) let alone many mains powered answering machines etc - so seemingly I must treat it fully as FELV if I'm to comply with BS 7671 chapter 41 - so I need cables insulated according to the voltage of the 'primary circuit' (mains?) and all exposed-conductive-parts earthed? Then, as you say, there's the 30mA RCD issue where the cables are concealed in walls.

Similarly the TV, aerial amplifier, sat box etc don't obviously meet BS 7671 limited definitions of SELV/PELV sources (and several inject a d.c. voltage to power LNBs, masthead amps or remote control eyes, so we can't really presume the only power source is the aerial). Maybe it would make sense to earth the screen of co-ax cables concealed in walls rather than going down the RCD route, but none of the cable types permitted by 522.6.204 (i) are suitable for UHF.

Or have I got completely the wrong end of the stick?

- Andy.
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Which bits of domestic wiring does BS 7671 cover?

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