ECN Forum Forums Photo Discussion Forums Photos for General Discussion Electric Whiskers

That's 6 thousandths of one rpm tolerance on a 3600 rpm alternator, 0.6%.
Alan

To expand my question a bit: As I understand it, the frequency of the net is very, very precisely regulated to 60.0000000 Hz over the long term, so that electric clocks will be accurate. I am unclear whether pdh was merely exercising a bit of levity, or if the actual standard is a bit off from 60 Hz, and clocks are designed to take that into account.

For comparison, the "60 Hz" field rate of NTSC television is actually slightly less than that, resulting in strange "drop frame" features in the SMPTE time code, among other things.

The 110V building site power here normally uses the very bulky connectors known as BS4343, CEEform, and other designations.

Click here to see 16-amp versions .

However, as far as domestic use is concerned, there's nothing in the U.K. to prevent the use of NEMA receptacles (or any other type for that matter).


The nominal frequency was adjusted down to 59.94Hz with the adoption of the NTSC color system. By contrast, the 50Hz field rate of British/European TV is still nominally 50Hz.

Paul,
Perhaps it should be pointed out that 110v is almost exclusively a UK 'building site' voltage, supplied by individual 240v transformers for safety reasons. Is this a legal requirement in the UK? If it's an EU directive, the French ignore it, because I've seen French tradesmen all using 230v kit, without hard hats on chantiers. Or proper guarded scaffolding for that matter, just those well named 'cripples' hooked over a pair of ladders with an old plank between.

In the uk, on building sites the "principal contractor" is responsible for site safety, and they must have insurance, which generally stipulates 110V (really 55-0-55V) on site for portable tools. So on most commercial sites anyone caught with a 240v tool will be dissmissed instantly.

HSE recommend the use of low voltage tools, but take a realistic view and recommend a RCD with 240V. Clearly self builders aren't going to have all 110V tools. You couldn't have and there isn't a law against 240V on site, as many big machines couldn't work on 110V.

It's interesting that hse allow 240v but are consficating pull-over mitre saws from work places.

Paul,

The 110V stuff is legally required for portable hand-held powertools on sites here in Ireland.

230V equipment (with RCD) can be used but, not handheld stuff.

SolarPowered: From some things I have read, the power grid sometimes fails to make up for every cycle lost in the times they do drop the frequency under heavy loads. As I understand it, if they can't make it up within a day or so, they just reset and move on. I've heard they have come out a few seconds short in the worst cases.

No one should be depending on them for accurate timing anymore, anyway.

I'm not sure of the exact details of the Health & Safety at Work Act, but this is one case where it's not an EU rule. The U.K. was using 110V site tools years before we even joined what was then the EEC.

We've had some discussions about 110V site tools before, such as this thread .


I'm not quite sure what type of miter saw that is, but who exactly gave the HSE any authority to confiscate anything? (Not meaning to go off topic -- Maybe this is a subject for a thread in non-U.K.).

I like PDH's description of the system as '55-0-55' volt, I must remember to use that, it describes much more accurately the reasons for using it (limited voltage to ground) than the usual description of '110 volts'.

So, to get back on thread, Randy, where IS that warehouse receptacle with American wire-nuts and '50 cycle 220v'?