EV Ultra Cable ( SWA 3 core with Cat 5). Termination ?

To terminate such a cable into an EV charger or other appliance, I would follow the manufacturers directions, and consider this to be outwith the IET wiring regulations and to be covered by the appliance approvals.

For connection to a consumer unit I would not take the cable directly into a consumer unit or similar equipment.

I would terminate the cable into an adaptable box or similar mounted immediately adjacent to the consumer unit. Connect a short piece of green/yellow to the armouring, via an earth tag. Take the three cores and the extra earth into the consumer unit and connect like any other circuit.

The ELV data cores should leave the adaptable box via a separate gland, spaced away from the insulated but no longer sheathed live cores.

I would consider it good practice to apply extra protection such as insulated sleeving to the data wires whilst in the same enclosure as the mains voltage wires. 

JHFE: 
 

 

It just seems a bit iffy to have a data cable ( by now unsheathed and stripped back )  entering a consumer unit.  A data cable that has a conductive shield.

 

looking at EV_Ultra_Datasheet.pdf (doncastercables.com) the data cables and screen are surrounded with another layer of insulation, so is insulated against the highest volatage present. There would be no reason to strip this insulation back within an enclosure, it would be brought through and exit to go its merry way to data central. 

JHFE: 
 

Looking at EV Ultra SWA 3 core cable with Cat 5 data and is raising a few questions.

It is aimed at EV charging installations, however…..

At some point that cable has to enter an enclosure and be terminated.  This could be directly into an EV charger, designed to take the cable, but it could also potentially be terminating at the power source end, into an enclosure with power terminations for the 3 cores ( line conductors and CPC ), e.g. a consumer unit.  

It just seems a bit iffy to have a data cable ( by now unsheathed and stripped back )  entering a consumer unit.  A data cable that has a conductive shield.

Is anyone aware of any regs that specifically allow or prevent this situation?  or is the case of  “allow” is that covered by section 134 and regs such as 134.1.1 “Good workmanship….proper materials……manufacturers' instructions.”  e.g. power elements and SWA terminated to CU with a gland, data cable suitably sheathed ( sleeved ) as it makes it's way back out of the CU to an appropriate ethernet connection?

Does the use of this cable type comply with BS 6701 for Ethernet (or indeed EIA 485) ? This standard is referenced for telecommunication cabling (which includes information technology and “data” cabling and controls comms) in BS 7671 (Regulation 110.1.3), and therefore to comply with BS 7671 you should also comply with BS 6701.

Clause 5.4.4.2 “Protection of telecommunications cabling and attached equipment” (which is not for EMC, that is 5.4.4.1, but “local regulations for safety” as stated in Clause 5.4.4.2) requires at least 50 mm separation between power and telecomms cabling, even with a partition or where the LV cabling is an earthed conduit or trunking, or in 'insulated and sheathed' flex!

However, that is only for indoor use … if the cable goes outdoors, it may require installing in accordance with BS EN 50174-3 and greater separation distances may be required.

Thanks chaps for all the sage advice and observations.  

I particularly like the method of the adaptable box first to separate the data and prevent it from reaching a CU, then taking only power into a switching enclosure environment.

As for the separation of power and data regs wise, my interpretation here is that while intact the cable is compliant by virtue of manufacturer specification.  Compliance for successful termination is down to the installer, in line with manufacturer guidance and relevant regulation/s.

I see this situation differently from that of services laid in the ground at different times by different trades.  IMHO, I would say that the regulations are to providing a means of compliance for a “manufactured on the spot, in the field” arrangement of power and data, as opposed to something designed, tested and manufactured in a controlled environment to exacting tolerances with quality control etc.

Otherwise, why are they bothering to make something that overzealous inspectors could C1 on every occasion?

Indeed - and ‘makers instructions’ if there are any, take precedence. Clearly inside the cable the cable makers rules about clearances apply.

If there are instructions, I imagine they would say something along the lines of “keep power and data apart once you have removed the outer sheaths”

I might slip a bit of sleeving or maybe even thin flexi-conduit over the innner cores once split out, until very clearly away from each other, if there was any doubt at all.

I too like the break-out box idea. A single point where the absolute minimum of mains voltages get close to the unsheathed data cables - much as you have with the computer /hub, IT rack  etc it connects to

Mike..

mapj1: 
 

Indeed - and ‘makers instructions’ if there are any, take precedence. 

‘taking account of manufacturer’s instructions' does not mean they take precedence over safety requirements.

BS 7671 only requires certain specific things, like luminaires, busbar trunking systems, maintenance free accessories to BS 5733, and semi-enclosed fuse elements, to be installed in accordance with manufacturer's instructions. Everything else is “taking into account” or “taking account of” etc.

Even then, what if manufacturer's instructions in a particular circumstance would contravene a safety requirement, or a provision in legislation in the UK because the instructions are developed in another country?

On these points I definitely agree with points davezawadi has made in the past.

Ok,  I think perhaps I could have worded that better - I agree the authors of the Chenglish sort of instruction ‘do not teach these fairy lite to swim’  and similar needs to be treated with the contempt they deserve.

But,  if the cable makers say that they have tested the isolation from the mains part to the data part at the same standard at 1kV or whatever, and there is evidence that it is a maker we trust, not just some 3rd world re-badge merchant, then we should be able to follow that, treating the segregation in-cable as we would treat segregation in trunking.

So I reword thus, I have no difficulty in ignoring a EU or BSI standard that did not foresee the current situation, providing the same level of safety is maintained by another method.

Edit  A link to the maker's data sheet

And a picture No need to remove the jacket and screen of the data cable until well away from the main cores.

If the standard thinks this construction is unsafe because of the risk that mains will end up on the data lines, the standard is probably not right. If it is a good idea for EMC over a long run, I am much less sure.

Mike

I am not saying the product is unsafe, but the practice (of using the product in a fixed installation as part of the data link) is arguably deemed to be unsafe by BS 6701.

To that standard, physical separation by minimum distance is required even if the data and power are in separate containment. It's not clear now a cable containing both power and data meets this requirement. 

BS 6701 also has increased minimum fire performance requirements for fixed installation cables that exceed the minimum in BS 7671.

(I'm not saying this cable doesn't meet those, I haven't checked … just that BS 7671 is not the only standard to consider here.)

 

looking again at the link i posted earlier EV_Ultra_Datasheet.pdf (doncastercables.com)

There is mention of only 2 BS numbers, for the conductors and the insulation. The cable itself does not appear to have a BS EN number, perhaps unsurprisingly as it is relatively new. This would mean the Designer confirming in writing that it provides the same degree of safety etc on any EIC in accordance with 133.1.3

I also noted the max CCCs quoted for 4mm and 6mm cables is the same as in Table 4E2A ref method C.

OlympusMons: 
 

looking again at the link i posted earlier EV_Ultra_Datasheet.pdf (doncastercables.com)

There is mention of only 2 BS numbers, for the conductors and the insulation. The cable itself does not appear to have a BS EN number, perhaps unsurprisingly as it is relatively new. This would mean the Designer confirming in writing that it provides the same degree of safety etc on any EIC in accordance with 133.1.3

I also noted the max CCCs quoted for 4mm and 6mm cables is the same as in Table 4E2A ref method C.

If that's the case, and there is no constructional standard for the cable, then from BS 7671 perspective, it's a bit like CY / SY / YY.