• They are defined as "couplers" in BS EN 60320, and again in Reg 553.2.1.

• BS EN 60320 appliance-outlets are not suitable for direct connection to the fixed wiring, they are part of equipment. Equipment should be selected in accordance with BS 7671 (i.e. meets relevant standards, suitable rating etc.)

• BS EN 60320 is not listed in Table 55.1, as required by 553.1.3 unless 553.1.5 applies, and the use you are alluding to for data cabinets doesn't really come under any of the exceptions listed in 553.1.5 - so if you want to specify them, they cannot be "socket-outlets".

They are defined as "couplers" ....  in Reg 553.2.1

AJJewsbury:

They are defined as "couplers" ....  in Reg 553.2.1

Saying that couplers must comply with BS EN 60320 logically isn't the same as saying all things complying with BS EN 60320 must be couplers - that would be like saying since sockets must comply with BS 1363 then all things complying with BS 1363 must be called sockets - and thus you couldn't have a BS 1363 plug.  (Or the classic example, since tables have four legs, all four legged things must be tables).

On a wider note, I'm getting less and less happy with the definition of a socket needing to be attached(?) to fixed wiring. There's no definition of fixed wiring (I could see that it could either be wiring that's not free to move, or equally, wiring that can't be readily unplugged from the supply and relocated). If following the example of 'fixed equipment' the former might be expected, but is there really a significant difference between a wall mounted socket and one of these? https://olsondirect.co.uk/4-way-13a-switched-socket-suspended-service-unit.html


   - Andy.

 

Hang on, that's picking at a single thing from a three-part reasoning.

Apologies - not having access to BS EN 60320 I can't see the context of its definitions, so I'm having difficulty commenting on that bit. While I can see that the usual female IEC connector on the load end of a flex would certainly be a coupler (or "connector" in BS 7671 definition terms), I still can't see how the panel mount version (connected to "fixed" wiring and intended to accept a C14 plug on the supply end of the flex) would fit the same BS 7671 definitions. Looking at it the the way around, trailing 13A sockets come under BS 1363 - the standard for socket outlets, but surely in BS 7671 terms they're couplers/connectors, rather than socket outlets, when connected on the end of a flex rather than fixed wiring.

I do see your point about BS EN 60320 items not being listed as being acceptable socket types - but again that of itself doesn't say to me it's not a socket.

If I stuck a schuko socket on a wall, I think the usual conclusion would be that it was a departure from BS 7671 (which may or may not be justifiable under 133) rather than it needed to be given the name of a different kind of accessory.

So far we seem to be saying that, in the picture of the PDU above, that the right hand four "outlets" are sockets as far as BS 7671 is concerned, and so require 30mA RCD protection (unless a risk assessment concludes otherwise), but the eight "outlets" on the left, are deemed not to be socket outlets, so have no such requirements - even though they're likely to be used in exactly the same way. That's a conclusion I'm not entirely comfortable with.

13A Socket -> Plug -> Flex -> Appliance - OK (30mA RCD protection required at or before socket)

FCU -> Flex -> Appliance (might be fixed or hand-held) (no RCD requirement)

FCU -> Flex -> BS 1363 outlet (as in the pendant socket mentioned before, or a autorewind reel with a trailing socket on the end of the flex) - apparently a connector rather than a socket, so no RCD requirement?

FCU -> Flex -> BS EN 60320 connector - similarly, no RCD requirement?

FCU -> BS EN 60320 panel outlet (directly hard-wired, no flex) - not permitted?

Bob C:

I have a Client that will not provide a Risk Assessment to omit an RCD Commando Socket for a Data Cabinet. He wishes to employ a local isolator for the Cabinet, however he is concerned that the PDU Strip that arrived on site from the factory and pre-fitted within the data cabinet would still need an RCD. It is my opinion that the Factory built Data Rack is classed as a piece of equipment and as such does not form part of the Contractor's installation. If the Rack had arrived on site without the PDU strip fitted and it was installed by the Contractor then this would form part of the installation and therefore would require an RCD. Any advice/assistance would be appreciated.

AJJewsbury:

Bob C:

I have a Client that will not provide a Risk Assessment to omit an RCD Commando Socket for a Data Cabinet. He wishes to employ a local isolator for the Cabinet, however he is concerned that the PDU Strip that arrived on site from the factory and pre-fitted within the data cabinet would still need an RCD. It is my opinion that the Factory built Data Rack is classed as a piece of equipment and as such does not form part of the Contractor's installation. If the Rack had arrived on site without the PDU strip fitted and it was installed by the Contractor then this would form part of the installation and therefore would require an RCD. Any advice/assistance would be appreciated.

Apologies for the apparent tangents - we're still debating the finer points.


So far we seem to agree that if the PDUs contain BS 1363 socket outlets then the 30mA RCD requirements would apply - so somehow or other that would need to be dealt with - either by a 30mA RCD in the supply circuit, or one or more 30mA RCDs within the PDU arrangement (or better still by risk assessment to eliminate the need for RCDs altogether - probably what most PDU manufacturers assume). Ditto if there are BS EN 60309 sockets (or even BS 546 sockets) rated 32A or less within the rack.


We seem to have mixed opinions still if other types of 'connectors' are used - e.g. the IEC 60320s chassis mount outlets often found on PDUs.


To me, trying to supply an IT rack without an risk assessment to omit 30mA RCDs is rather like trying to run a taxi service without a driving licence - while it's not impossible, the contortions you have to go through (hard wiring things that should be pluggable, perhaps needing 30mA RCDs when they're not really needed) make it a very dubious choice in the long run.


  - Andy.

 

 

FCU -> Flex -> BS 1363 outlet (as in the pendant socket mentioned before, or a autorewind reel with a trailing socket on the end of the flex) - apparently a connector rather than a socket, so no RCD requirement?

I think this is a socket-outlet, or an accessory with socket-outlets, so I think 411.3.3 (i) applies.

Bob C:


I have a situation where some of the IT cabinets are 3 Phase and I dread the thought of an IT Technician interconnecting the power to dual fed Servers for obvious reasons.