Doing as asked

[winston1]

However the point is tradition has been to power items from lights, be it a fan or TV signal booster it is normal, and with wallmart power supplies (not calling it a transformer) to power TV boosters or LED lighting strips then we really have no option but fit 13A sockets to lighting circuits,

No you have the option to fit a socket to the ring circuit. TV boosters can and are usually powered up the coax cable from a power supply next to the TV plugged into the ring.

Be it no FCU which will take 16A fuse, or no option but use 13A socket one has to work with what we can get, so we often have no sensible option but use a 13A socket on the lights.

Why can't we use a 13 amp socket on the ring?

 

[bernardgreen]

If R is zero the power will be zero.

If R is zero the wires in the fan are at 0°K

 

[JohnW2]

It won't. Power =I squared R. If R is zero the power will be zero.

I don't think bernard should have written "...in the fan", since what you say would be true of the fan itself. If the fan itself became an impedance of 'zero', the 4kW (or whatever) would be dissipated, but in the circuit's cables (until something cleared the fault), not in the fan itself.

Kind Regards, John

 

[winston1]

Much of the 4kW would be dissipated in the MCB but not for long (enough to worry about).

 

[JohnW2]

Much of the 4kW would be dissipated in the MCB but not for long (enough to worry about).

I would have thought that the impedance of the circuit's wiring would be very much greater than that of the path through the MCB (which, after all, is only two or three inches of sturdy wire and a closed pair of switch contacts), in which case the great majority of the energy would be dissipated in the wiring, rather than the MCB.

Kind Regards, John

 

[winston1]

I would have thought that the impedance of the circuit's wiring would be very much greater than that of the path through the MCB (which, after all, is only two or three inches of sturdy wire and a closed pair of switch contacts), in which case the great majority of the energy would be dissipated in the wiring, rather than the MCB.

Kind Regards, John

Maybe, bit it would not be for long enough to worry about.

 

[JohnW2]

Maybe, bit it would not be for long enough to worry about.

Indeed so - that's what fault protection is all about. If the cable is adequately protected by the OPD, then it (the cable) will not suffer from a short circuit at the end.

As I often say, the one argument for 'fusing down' is that it might conceivably reduce the damage to the load in the event of it becoming faulty (although we all agree that there should be internal fuses to achieve that). With a small fan run from a 6A circuit, I wouldn't bother at all, but if I was going to have to 'fuse down' anyway (e.g. if I were running the fan from a 32A circuit), and therefore had to use an FCU, I would probably put a 1A fuse in it.

Kind Regards, John

 

[EFLImpudence]

There is no need for them on lighting circuits.

I agree with you BUT you keep saying they AREN'T USED which is patently untrue.

 

[ban-all-sheds]

To drag this, and the other more recent one, now locked, back on topic, the issue here, and with the other one, is not what Winston wrote, it's the way that the moderators repeatedly shut down any criticism of him which he gets because of what he writes. In the garage lights topic they even removed the post from the OP where he said Winston was wrong, but they made sure to leave Winston's post alone.

They support and protect him, as a matter of site policy, and as you can see from the quoted post on p1 they try to deny this. As I wondered in the other topic, how much evidence is needed before they admit it, and stop?

Presumably even they realise that they shouldn't dare do that in this particular topic, but this one will pass, and sooner or later they will be back to their standard behaviour.

 

[winston1]

There is such a thing as freedom of speech (and freedom to express ones views on forums). You have a right to disagree with what I and others say, but that does not extend to insults and rudeness.

 

[winston1]

In the garage lights topic they even removed the post from the OP where he said Winston was wrong, but they made sure to leave Winston's post alone.

The OP did not say I was wrong, he said that I was correct electrically.

Anyway my post does seem to have been removed.

 

[ericmark]

I have very rarely found the rating of a MCB or RCBO was too low for the prospective short circuit current, when I did I had to rake out my old text books to find out what to do, and they talk about a let through valve for the fuse, so if you fit a fuse to feed the MCB then it is not the measured PSCC that matters but the let through valve of the fuse.

I could not find all the info I wanted, however I fitted a fuse holder and a 40A fuse I seem to remember in the tower cranes panel to feed the RCBO which fed the 13A socket which had the charger for banks man's radio. But on retesting the resistance of the fuse was low enough so the PSCC was within limits.

So never had to use the let through valve, however the same will apply to a house, the let through valve of the DNO fuse means the PSCC will always be within the limits.

But the resistance of the fuse can also cause problems with volt drop, using 2 fuses in series as happens when you use an extension lead can cause problems, but as far as I am aware the only items in the home where volt drop is a problem is fluorescent lights and fridges and freezer and air conditioning units.

So there is no real problem having a 1A fuse feeding a 13A socket which has a wallmart in it to power LED lights.

 

[phatboy]

This all seems accurate - winston1 seems untouchable, even when he is posting nonsense.

He is one of the reasons (I suspect) that people get scared away from posting here. Is it a transformer, is it a switch mode PSU - does it really matter if we all know what was meant?

Pedantry is risking the entire forum section, and winston1 is the main culprit.

I had him blocked for a considerable time - only reason I unblocked is threads made no sense.

 

[JohnW2]

He is one of the reasons (I suspect) that people get scared away from posting here. Is it a transformer, is it a switch mode PSU - does it really matter if we all know what was meant? ... Pedantry is risking the entire forum section, and winston1 is the main culprit.

Very much so.

However, although winston has a few very tedious bees in his bonnet, he is not the only person here who believes that people should be corrected when they use 'incorrect terminology' (or even 'incorrect English'), even though "we all know what was meant" - things like "low voltage lights", "plug tops", "ring mains", "double-insulated cables", "fused spurs" (referring to an FCU) etc. etc. (or even colloquially, but not appropriately, starting a sentence with "So"!).

Kind Regards, John

 

[EFLImpudence]

What is the outcome when people never have mistakes corrected?