E.L.V. Garden Bollards.

I agree that my proposal might not comply with the regulations. In view of the negligible risks, it would however be a reasonable departure.

AJJewsbury:

522.8.10 is obviously aimed at L.V. not E.L.V. The use of the expression "suitable for use as a protective conductor" is a give away..

I don't think that adds up - you can have protective conductors on ELV - both FELV and PELV - and LV systems without protective conductors are possible too - e.g. separated systems for single items of equipment and fully double/reinforced insulation (a c.p.c. has to be included for the latter in domestic and similar uncontrolled installations of course, but as a general principle it's not required).


Given the wording and position of 522.8.10 I don't think it can avoided as reading that it should be applied to all systems - if it was intended as applying onto the ADS systems only then section 411 would have been a more obvious location for it for example. Some might think that many of the other provisions (depth, marking tape and so on) would be sensible for any system. I guess they're expecting us to use the conduit/duct option where there isn't a c.p.c. The near-by regulations for cables concealed in walls have an explicit get-out for SELV & PELV circuit - so clearly the 522 section in general is intended to be read as applying to ELV too.


A while ago in response to one of the DPCs I did suggest an exemption for SELV at least for the earthed sheath/armour bit (and I gather through the grapevine that it was discussed - so the committee are aware that it is being read as applying to SELV/PELV systems) but seem to have decided not to change it.


   - Andy.

Section 522. SELECTION AND ERECTION OF WIRING SYSTEMS IN RELATION TO EXTERNAL INFLUENCES.


That's bashing, and prodding stuff, drilling  or nailing through, and high temperatures, water problems, dirt, grime and dust etc.


522.8 is about other mechanical stresses. This covers bending radii, conduits and supports etc.


Then there is 522.8.10. It is all embracing, and it covers cables in the ground, and following on from conduits obviously is concerned about using conduits or ducting and use of them as a protective conductor where applicable,  More concerns about Low Voltage than bell wire at E.L.V.


So, just what does BS EN 61386-24 say about underground conduits?


 A S.E.L.V. supplied circuit, not exceeding 12 Volts A.C., does not even need basic protection of live parts, a bit like an electric model railway with live tracks, so why bother with earthed conduit for underground S.E.L.V. circuits. I agree that the mechanical protection will be valuable, but earthed conduit is expensive and disruptive to install in a lawn and it might make the grass change colour along its route. 414.4.5 last sentence. 


Nah, the reg. covers L.V. in its concerns, not E.L.V. That was its intention.




Z.