Garage electrics

[ban-all-sheds]

I haven’t bought a welder as yet it’s something I’d buy in the future, it would only be small to weld cars

And then you find that a small one is too small. Or you'd like a compressor.

IMO 10mm² is the minimum you should consider.

 

[JohnW2]

Not if you select Lighting Circuit - it taps out 6mm at 5875W.

... but does anyone really care if the VD is a little bit over (the 'recommended', for lighting circuits) 3% - particularly if, like so many of us, one's normal supply voltage is more than 4% above nominal, anyway?

Kind Regards, John

 

[ban-all-sheds]

Once you start saying it's only a little bit over the VD limit/speed limit/weight limit/etc, where do you stop, and how and why?

You imply that you don't care if it's a little over 3% - is there an official definition of "little"?

If we went back and forth narrowing in on a figure > 3 and < {something}, would we reach a limit with which you were happy?

 

[JohnW2]

Once you start saying it's only a little bit over the VD limit/speed limit/weight limit/etc, where do you stop, and how and why? You imply that you don't care if it's a little over 3% - is there an official definition of "little"? If we went back and forth narrowing in on a figure > 3 and < {something}, would we reach a limit with which you were happy?

I haven't tried with the TLC calculator myself, but assuming that bernard and yourself are telling the truth, the implication is that we're talking about a VD, with the full design current of the circuit flowing, of between 3% and 5%.

You talk as if there is a regulation requiring a maximum VD of 3% for lighting circuits although, as you know, there is none. In the absence of a specified minimum voltage in a 'relevant product Standard' (I'm not convinced that that hardly ever applies) the only regulatory requirement is that the load (of whatever sort) should be supplied with a voltage which does not "impair the safe functioning of the equipment" - and I would certainly struggle to think of any way in which even a very low voltage could "impair the safe functioning" of any sort of lighting equipment.

In any event, if one really is concerned about VD, one would need to undertake more appropriate calculations than what happens if one plugs figures into the TLC calculator. That will only give correct answers (if it ever does) in terms of VD if (a) the supply cable (6mm² or 10mm² in this case) go all the way to the final loads and (b) that lighting equipment is connected to the wiring at exactly the same place as the other (usually predominant) loads - neither of which conditions is usually satisfied. In particular, lighting often branches off the main 'power' cable an appreciable distance from the major loads, so that the VD as seen by lighting equipment will commonly be appreciably lower than the simplistic calculations would suggest.

Kind Regards, John

 

[Lectrician]

10mm minimum. 6mm is a compromise, saving so little money.

 

[ban-all-sheds]

You talk as if there is a regulation requiring a maximum VD of 3% for lighting circuits although, as you know, there is none.

Quite right - I remembered that last night.