Who's rewired their house for this hobby?

tony duell ard at p850ug1.demon.co.uk
Sun Nov 23 14:18:40 CST 2014


> 
> I note that the higher-power vacuum cleaners ("hoovers") are being
> limited in the UK.  I was always envious of those.  A typical "high

Yes, another moronic EU regulation. No idea what the point of it is, 
probably to please the 'greens' (as I have said many times, when I was a 
kid. 'green' meant 'naive', and I don't think it has changed much...

There was talk of them limiting the power of electric kettles. Come again?
Last time I looked, to raise a given volume of water from a giving starting 
temperature to 100_C and then to vaporise it took a defined amount
of energy. The specific heat capacity of water, and the latent heat of
vaporisation are known physical quantities, not something you can
pass (political) laws about. In fact due to heat losses in the kettle, the higher
the input power, the _more_ efficient it is.

> power" vac here is 1200W.  NEC (our electrical code) says that corded
> appliances may not draw more than 80% of the rated load capacity of a

I feel the rated load capacity of a circuit should be just that. An outlet
rated at 15A (say) should be able to supply 15A for ever.


> non-dedicated circuit.  For most US homes, standard wall receptacles are
> 15A/120V, so that limits the draw by any individual appliance to 12A.
> The section (210.23(A)(1)).is a bit more complicated than that, but you
> get the idea.

What do you do about electic kettles, portable electric heaters, etc? 

Even portable power tools? Industrial portable power tools (electic
drills, etc) in the uk, if not run off internal batteries are 110V. We
run them of an isolating transformer with the centre tap of the 
secondary winding connected to earth. The idea is that in the event 
of an insulation breakdown so an exposed part ends up conencted
to a live part of the tool the maximum voltage the user can get is
55V RMS. Which is painful-ish,  but unlikely to be fatal.

Anyway. I have a 110V angle grinder here which is specified to have
a full load current of 28A (!)

> 
> On the other hand, we aren't troubled with ring mains.  There's also no
> danger of using a 13A plug fuse for a table lamp--we don't need no
> stinking plug fuses!

No, instead your table lamp is protected by a 15A breaker in the 
distibution panel. Hmm.. I am told that in some continental 
European countries it's common to have a pair of 16 A (230V)
outlets protected by a single 32A breaker. And no other protective
device. So a table lamp is effectively fused at 32A. No thanks.

I can't be the only UK-classiccmper to have a large jar of new
13A cartridge fuses removed from new plugs that I am fitting
to <whatever> and which I have fitted with a 3A fuse. Actually the
reputable manufacturers will supply plugs fitted with either a 3A
or 13A fuse (in the case of MK (think of them as the UK version of
Hubble), the only difference between the 2 types is the fuse, it is
quite safe to take a 3A fused one from the factory, fit a 13A fuse and
use it on a 3kW electric heater, I have checked this with them). The
only problem is that very few places stock the ones with 3A fuses
in them. 

About 20 years ago a local (then) department store mis-ordered 
MK plugs with 3A fuses. Deciding that they were useless, they put them
on sale at 1/4 (about) of list price. I bought all they had on show and 
asked if they had any more. Yes, another 50 in the stock room. I bought 
those too. They couldn't understand why I wanted them.

-tony



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