Then he'll face another problem of creep in the terminations - ali conductors in screw terminals need to be on a maintenance cycle of retightening. Had that at work - a neutral fell off a DB board and the resultant overvoltage on one phase blew a few computers up.
Not sure where ali stands with crimps - they do crimp the joints in the road these days (and have used ali there for along time) but those crimps are made for the job - not sure how regular ones would fare?
Yes - they are called departures on the certificates.
For 100m 2.5mm, 10A = 18v drop CFL & heat lamp will have no problem with that, so you've got options
NT
You need to use terminations designed for al. Others are just not reliable.
NT
V drop is only the overriding issue if there's a good reason to keep it very small. I've not yet heard one. A lambing shed is not a domestic install.
NT
Hmm, some random questions about the difference...
What's the rule for a power circuit with a fused spur with wired-in lighting? What if the fused spur with fixed lighting is added later?
Why are lights on a lighting circuit different from portable lights plugged into a power circuit?
In any case a departure from the 3 or 5% figures in Table 12A (Appendix
12) would not necessarily be a departure. All appendices (except Appendix 1) are only 'informative'.The actual requirements for voltage drop are in regulations 525.1 to
525.4. To précis:525.1 says that you must observe the minimum voltage given in any relevant standard for the type of equipment concerned. (For many product standards this is Uo - 10%, i.e. 207V.
525.2 If there is no relevant standard the voltage must be "such as not to impair the safe functioning of that equipment."525.3 Gives 'deemed to satisfy' status to the Appendix 12 values for the above regs. - so naturally it's what's normally used.
525.4 Allows greater voltage drops for inrush currents (motor starting, etc.), provided product standards or manufacturer's instructions are observed.IME Using the bare minimum cable size is often something you come to regret. Professional designers quite commonly go up two size steps from the minimum.
Also bear in mind - especially if long term loads are involved (high load factor) - that the saving of lost energy can soon pay back the extra cost of a larger cable.
And the minimum size allowed is 16 mm^2 (Table 52.3).
In essence for 300 quid's worth of cable it's not worth the buggering about.
Is that price based on TLC prices?
Yes, and probably steep delivery for such a weight, I don't have access to 'trade' prices ... sounds like it'd be worth an ask?
Sensible design is a good reason. You have no control what someone is going to plug into a waiting socket, who does not know the built in limitations of the installation.
True. But if there's a 20A MCD at t'other end...
He'd probably just jog across the road to the house.
Definitely not. I know this because the single phase transformer is sat up a pole behind my garage.
Plugging a 13A load into a cable that produces over 4% v drop is not a problem. The only loads that get touchy about it are fridges: rarely fail on slight undervoltage incandescents: harmless, not the lighting of choice today
NT
which has the same R as 10mm copper, but is cheaper.
NT
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