2.5mm Spurs - Why?

[securespark]

Nah. Only be 15 pages

Aharrr Jim-lad!

 

[ban-all-sheds]

Nah. Only be 15 pages

Seems like a somewhat OTT wedding to me.

 

[aesmith]

One double outlet is permitted because the standard for socket outlets doesn't rate them for 26A (it's more like 10A in one and 4A in the other) and it's exceptionally unlikely that two 13A loads would be connected there.

I believe it's 14A plus 6A giving the often quoted 20A figure. However it's not clear if that's a minimum - meaning the double socket wouldn't comply with BS1363 if it didn't support at least that load, or an across the board maximum - meaning circuits can be designed on the assumption of a 20A max to a dual socket.

MK and Hager technical information doesn't give ratings for their dual sockets, in fact the absence of an overall rating implies 13A per socket = 26A. Unless I've missed it.

 

[ban-all-sheds]

AIUI 14+6 is what a socket has to demonstrate it can support indefinitely without overheating etc.

There is absolutely nothing stopping anybody making one which can support 14+14 without even getting barely warm.

The problem with circuit design is that you can never be sure that someone won't use a socket which can only manage the minimum required.

If BS publications were pretty much freely available, and the funding of them paid for by businesses who wanted to claim compliance, important information would be more likely to be better known.

 

[plugwash]

AIUI 14+6 is what a socket has to demonstrate it can support indefinitely without overheating etc.

The test duration certainly won't be indefinite. Also it will likely be done with brand new parts, not old worn ones.

There is absolutely nothing stopping anybody making one which can support 14+14 without even getting barely warm.

Nothing but the normal economic pressures.

The problem with circuit design is that you can never be sure that someone won't use a socket which can only manage the minimum required.

More generally the whole ring circuit/BS1363 sockets system is built around the assumption that load will be spread around. That applies to the sockets, it applies to spurs and it applies to the main ring cable itself.

If BS publications were pretty much freely available,................. important information would be more likely to be better known.

Agreed, locking up important technical standards behind paywalls means that the details of those standards are effectively hidden.

 

[ban-all-sheds]

The test duration certainly won't be indefinite.

No, it isn't, it's limited to 8 hours, but it is designed to show that the socket will not overheat in normal use, and in normal use you don't know how long it might be in use.

 

[AndyPRK]

The double socket could also be on the end of a 4mm^2 radial in a utility room.