Where I work,we would not normally test a rack to BS7671 unless it contained something that was essentially fixed wiring. We would however treat it like an appliance,or an extension lead and many appliances depending on the internal configuration.

Mike

Hi Mike,

Thank you for your quick and helpful reply. I don't believe any part of this will be like fixed wiring, though I did wonder about PLCs and things that have the power cores wired to individual terminals rather than being in a single IEC power cable. The power terminals themselves I understand to be under LVD scope and therefore covered by UKCA marking, however beyond that I was wondering about wire sheath colours and if ground connection rules might differ between the UK and USA.

Will

Is the rack expecting single or 3 phase supply?

Easiest is to have a bs4343/en60309 incomer if you can, and then define the supply requirements - eg 32A single phase or 16A 3 phase or whatever and  the overload and cable protection becomes the responsibility of the customer,

In simple situations it is often easier to buy in ready made block and bolt it in if you are not tooled up for making it. LVD will set requirements on IP rating, creepage and clearances.(Companies like this make a living selling ready wired cables and making unusual distribution blocks to order if a normal extension will not do.)

Single phase UK colours for wiring are Brown (live 230V to ground) Blue (neutral - almost 0V to ground) and Green/yellow (earth - what we call what you call ground ...)

Wiring should survive a 500V DC test between L+N to earth and manage and have an impedance of many megohms, probably hundreds of megs when new.

Reduced test voltages if surge arresting components are fitted and cannot be isolated during testing.

It would be easiest to use UK mains lead to make up internal wiring. At the least the devices with their leads attached, should then be tested to a level equivalent to a PAT (earth continuity, insulation of supply conductors from earth when dead, and leakage current and total power consumption when switched on).

If the components in the rack are already CE marked then there is a large part of the work done.

If you are adding earth studs to the rack, then I suggest to go for M6 threads- it meets everyone's requirements I caution that the American use of something in a UNC that we cannot get a replacement nut for that is under 4mm diameter does not impress UK eyes !

Mike.

Will D said:

The US-based company I work for needs to send a 19" rack cabinet of computers, PLCs and network equipment to the UK for temporary installation in a research facility. We've been advised (quite rightly) that we need to ensure compliance with UKCA marking requirements and be able to provide a technical file for this.

Is that true for all temporarily installed equipment - I'[m sure there are 'opt-outs' for temporary test, R&D, etc equipment? I guess it depends on the actual purpose, and of course checking to see if the essential requirements are met is always recommended at least for H&S reasons ... certainly, on the safety side, if the normal UK safety standards are not met, other measures would need to be put in place to mitigate any hazards.

Will D said:

However as this will be a cabinet "installed", i.e. fixed, in position, with power distributed within it, I wondered if it is also in scope of the BS 7671

Possibly, at least in part.

Certainly the earthing should be checked for compliance with Section 543.7 of BS 7671 (although note this changed in 2022, for example 'dual earth terminal' is not longer a requirement, but of course can still be selected by a designer), and also earthing checked to BS EN 50310 at installation (ultra-low resistance ohm-meter or micro-ohm-meter test).

I've installed a fair bit of US originated kit in the UK over the years (IT kit in racks normally), all according to the supplier's instructions.  The black/white/green core colours in the flex can be dealt with by over-sleeving at the terminations on the "UK" end. Voltages are usually OK but worth checking - we typically won't have 115V available, and 230V will have a earthed N - whereas US 230V is typically from a 115-0-115 system - so PDUs come with DP MCBS - which is fine if overkill for the UK. Just check that there aren't any 115V items lurking in there anywhere (small things cooling fans for the top of the rack come to mind).

   - Andy.

Much of what we do is R and D or temporary ,and the legal advice has always been to always UKCA or CE mark if there is money or benefit in kind changing hand, even business to business when the recipients do not want or need the marking for their own purposes.

That said, the technical effort behind deciding it is OK to stick the label on varies a lot between organizations ,and on how much the components involved have already been tested by others.

Free-issue loan or demo equipment, is less important but as I understand it, there is no exception in law for things that have a price, temporary or R and D.

The exception we do occasionally use is for self assembly kits - if the customer gets a bag of bits and then builds it themselves in some way then, apparently, they are the manufacturer, not us.

However, a legally very dim view is taken of trivialization of this route- such as supplying near complete kit but without a plug or a single lead that the user fits,  it has to be fairly "significant assembly", whatever that really means in practice.

Mike.

typos edited for clarity.

It will receive a single phase supply. Thanks for the suggestions, especially on the earthing studs! I'll pass those on.

Thank you Graham, very helpful.

I wanted to avoid looking for "loopholes" as we don't want to risk the equipment being rejected. Technically this is neither a loan nor a demo, nor a sale or benefit in kind or anything like that. The equipment will remain in the possession of our company and will be installed for testing purposes at the research facility of the host. The host will provide us with space, access, power and networking. I think the key thing for us is to understand how they will provide the power and what their site-specific requirements for our cabinet are.

Hello, thank you for the helpful suggestions. the cabinet is already wired so if we're not using the right colours oversleeving is probably the quickest solution, unless we find that the cable itself is not properly rated. We've already got a PDU in there: https://www.startech.com/en-us/server-management/pdu08c13h.

I feel at this point there's a risk that I start listing all the components and eventually providing a wiring diagram which probably isn't appropriate so I won't keep going. You've all been very helpful and I don't want to take advantage of that.