power limit for connection to a ring main?

[Christian McArdle]

Wrong. They should design for 230V +/- 10%. You DO NOT design for 240V. You design for 207V to 253V (minimum range) and you call it 230V.

Then you'd get the sack. You would need to design it for 230V +/- 10%. It must work and be safe at 207V to 253V. It must work in all European countries and it must work for the full range of possible voltages within those countries. Protective devices and ratings should be OK at the nominal

230V. Their ratings already incorporate the fudge factors to be safe as a resitive load at 253V. i.e. a 13A @ 230V resistive appliance is OK on a 13A plug, because the fuse, socket and plug are rated to provide protection at 14.3A @ 253V.

It WAS commonplace. It is now not permitted to design such appliances, except for incandescent lightbulbs. You would not get a CE mark. You would not be able to sell the product to a consumer within the EU.

Christian.

[Dave Fawthrop]

| > Anyone designing something for use in the UK has massive documentary | > evidence that it will be used at 240V, and rightly will design and rate | for | > 240V. | | Wrong. They should design for 230V +/- 10%. You DO NOT design for 240V. You | design for 207V to 253V (minimum range) and you call it 230V. | | > The 230V figure is only a political fudge to allow stuff designed | > in the EU to be sold here. If I were designing something in say France | > for use in the UK, I would design for 240V. | | Then you'd get the sack.

I spent 25 years designing little power stations for aircraft. We designed for 115V 3 phase 400Hz nominal. The tolerances were so well known they were never mentioned.

[manatbandq]

It was a rhetorical question to try and get meow2 to think about what he was saying!

MBQ

[Andy Wade]

No, because the temperature in an airing cupboard could exceed 30 deg C, which is the max. ambient temperature specified in BS 1363.

Indeed.

[David Hansen]

On Wed, 9 Nov 2005 18:04:10 -0000 someone who may be "Christian McArdle" wrote this:-

I assume a not is missing from that sentence.

Those who disagree with me are mixing two points that are separate. Whether they are doing so deliberately or accidentally I have no idea, but it doesn't do much for the credibility of their arguments.

So, let my repeat myself.

Point 1 - should an immersion heater be connected to a ring final circuit? The answer is that it is strongly discouraged. A separate radial circuit is strongly advised, because heavy and steady loads from large water heaters are best separated from general power circuits.

Point 2 - how should the heat resisting cable from an immersion heater be connected to the fixed wiring, be that a ring final circuit or a separate radial circuit? The answer is that a plug and socket is not really up to this, especially in an airing cupboard. It is good practice to use another method of connection, such as a cable outlet, switch, or fused connection unit (with or without switch).