Re: [CAD_CAM_EDM_DRO] Re: Re[1]: FYI: Home Depot Good buy on conns/cables 20' 3...

Hi,

Thanks for the information, especially Bill. Other comments in message
below...


From: <ballendo@...>

> <snip>to your homes and, even more surprising that both phases may be
> available at a wall outlet! Can this be true??
>
> Yes. Why is this surprising?

The impression I have of the US is that you go out of your way to make
everything 'safe' - even to the point of not having kettles that boil water
hot enough to brew tea! I would have thought that the potential danger of
having different voltages available in close proximity was quite a risk.
Presumably though, you do use different and non-interchangeable plugs for
110 and 220volts?

>
> <snip> and at the quaint way you still use what we used to call
> 'screwits' to join wires - a method which was banned in the UK in the
> '60's.
>
> Are you referring to wirenuts? What method is used for this type of
> connection in the UK?

Yes, I think that's what you call them - the plastic or porcelain caps that
you screw onto twisted wires. Actually, I used to think they were quite a
neat idea but they were banned over here quite a time ago. Now all
connections are made using screw terminals, either as brass blocks with a
clamping screw within fittings or as 'chocolate blocks' - plastic strips
having a number of brass tubes in them, each with two screws for clamping
the wires. While the screws are shrouded and usually covered, they do have
the disadvantage of still being accessible and therefore somewhat
hazardous - on the other hand, it easier to get at the screw heads to do
voltage measurements.

>
> <snip> (and are less expensive than their British counterparts)
>
> With their size and structure, its amazing your(UK) plugs are even
> affordable at all :-) Glad I don't live in a house with those
> large,blocky,fused plugs. Having 220 at EVERY outlet, tho...
>

Yes, they are a bit of overkill but you do need a certain size to get hold
of - particularly as the old hands start to get a bit arthritiky. I'm
intrigued that you say the two 'phases' of your power come from a centre
tapped transformer - does each house have its own transformer or is power
brought into the house on a four wire system? If the latter it must be
quite expensive to lay service cables compared with ours - a two-cored, lead
sheathed cable - the lead sheathing being connected to earth at the power
station and to other earth spikes at various points. Its also required on
new buildings now to fit a RCCD breaker at the fuseboard (the type that
monitors the current balance between 'live' (hot) and 'neutral' wires and
assumes that any imbalance represents a fault condition and so trips.

I've never understood why there has not been an international agreement on
wire colours. Over here on single phase (240 volt) 'live' (hot) is brown,
'neutral' is blue and 'earth' is green and yellow stripes. On three phase
415 volt 'internal cabling', all the 'lives' are either white or red and the
neutral is black whilst on large cables (like 16mm SWA and above) the three
phases are colour coded red, blue and yellow with a black neutral. So, if
you find a piece of British equipment with a white and black wire in a
connector, it might not be 110v hot and neutral, it might just be 240v
neutral and hot as one phase of a 3 phase circuit!


Ian
--
Ian W. Wright
Sheffield UK