Wiring a plug

[ericmark]

This can go into infinity, however with maths it does matter what grade, 'A' level is grade 3, but not sure if that is the same as 3rd grade? And with 'A' level in advanced maths they do imaginary numbers. But not is seems with normal maths, so when setting a question to solve quadratic equations it is rather important to ask for 'real' answers, or students who have done imaginary numbers can spend a long time trying to work out the answers where it was expected the answer was there was no 'real' answer.

We see the same with electrical questions, in the main volts x amps = watts, it is only when we advance do we say volts x amps x power factor correction = watts.

Also as the trade branches, what is expected changes, I remember moving into installation and being told how important not to mark the gland, so must use spanners, pipe wrenches were a no no. And I was taught one terminal has one wire, moving to domestic where three wires are stuffed into one terminal went against the grain.

As as to cable carrying capacity, the currents in the auto side of the trade are a lot higher. And with vehicles we did things which one would never do with low voltage. And the idea of changing the use of a pin in a plug, seemed daft, but pin 2 with a 7 pin trailer plug has changed what it is used for so many times. Vac warning, inertia light, reversing lamp, rear guard fog warning, so pin 2 always fused.

And when head lights were wired as pairs we would never fuse, only when it went to left and right did we fuse, I remember one vehicle used an auto resetting over load, driving at night when head lights go out is not funny, then just before you hit some thing they come back on, seem to remember CF van but may have got it wrong.

The same with live dependent machines, seems medical items can have a 13 amp plug without a fuse? Seems wrong to me, but seen the red NHS plugs with no fuse.

 

[SUNRAY]

This can go into infinity, however with maths it does matter what grade, 'A' level is grade 3, but not sure if that is the same as 3rd grade? And with 'A' level in advanced maths they do imaginary numbers. But not is seems with normal maths, so when setting a question to solve quadratic equations it is rather important to ask for 'real' answers, or students who have done imaginary numbers can spend a long time trying to work out the answers where it was expected the answer was there was no 'real' answer.

We see the same with electrical questions, in the main volts x amps = watts, it is only when we advance do we say volts x amps x power factor correction = watts.

Also as the trade branches, what is expected changes, I remember moving into installation and being told how important not to mark the gland, so must use spanners, pipe wrenches were a no no. And I was taught one terminal has one wire, moving to domestic where three wires are stuffed into one terminal went against the grain.

As as to cable carrying capacity, the currents in the auto side of the trade are a lot higher. And with vehicles we did things which one would never do with low voltage. And the idea of changing the use of a pin in a plug, seemed daft, but pin 2 with a 7 pin trailer plug has changed what it is used for so many times. Vac warning, inertia light, reversing lamp, rear guard fog warning, so pin 2 always fused.

And when head lights were wired as pairs we would never fuse, only when it went to left and right did we fuse, I remember one vehicle used an auto resetting over load, driving at night when head lights go out is not funny, then just before you hit some thing they come back on, seem to remember CF van but may have got it wrong.

The same with live dependent machines, seems medical items can have a 13 amp plug without a fuse? Seems wrong to me, but seen the red NHS plugs with no fuse.

Years ago in public entertainment we could get a license (that's what it was always called but might have been a cert etc) to use type approved 13A plugs followed by a 16A double pole MCB, it was only a couple of wholesalers who knew about them and would supply to order. They were always an MK plug, orange 3x2.5mm² pvc flex and a box containing DP MCB and 1x16A or 1x13A or 2x13A socket, they were serial numbered and the license covered only one device. The big problem we encountered was the limit of 1m of flex often meant it was suspended in mid air.

Lots of the Vauxhalls/Bedfords had the thermal trip on headlights (in the days of a 4 way fuse box), the first I knew about then was my Viva HB when putting my hand up behind the dashboard and burning a finger. It was a bi-metalic strip mounted on a plastic base with no cover, thinking about it now a pretty horrible device bearing in mind it's unfused battery status and unintended contact.

The difference between commercial and domestic electrics if incredible and the average 'house basher' cannot understand that when dropped into a commercial situation. No offence intended just very different environments.

 

[ebee]

Lots of the Vauxhalls/Bedfords had the thermal trip on headlights (in the days of a 4 way fuse box), the first I knew about then was my Viva HB when putting my hand up behind the dashboard and burning a finger. It was a bi-metalic strip mounted on a plastic base with no cover, thinking about it now a pretty horrible device bearing in mind it's unfused battery status and unintended contact.

The difference between commercial and domestic electrics if incredible and the average 'house basher' cannot understand that when dropped into a commercial situation. No offence intended just very different environments.

Interesting, thanks Sunray. Oh and the Orange MK plug with 3 x 2.5 conductors, another interesting one.

 

[JohnW2]

Yes I do 6.0 T & E for cookers

4mm² may, of course, be in adequate for a 32A circuit (because of installation method) but are you saying hat you use 6mm² even when 4mm² would be adequate?

One more reason is less different sizes to keep in stock too.

If I were a 'discerning customer' and my electrician proposed to use larger (hence more expensive) cable than was actually needed "because that's what he/she {I hesitate to write "they" ) had in ther van", I might be inclined to say that, whilst i Had no problem with that, I was only prepared to pay for the smaller cable that would have been adequate!

4.0 was not well favoured for radial circuits by lots of us although some did use it.

As above, 4mm² would not always be adequate for a 32A radial - but are you really saying that they used 6mm² - or did they just not install 32A radials

1.5 was pretty common many years ago on lighting circuits then copper costs went sky high so 1.0 became norm to many if the circuit allowed it (most domestic lighting circuits did) and it`s easier to use so 1,0 eventually became quite common.

The impression I get from what I see and hear, here and elsewhere, is that 1.5 mm is still widely (but totally unnecessarily) used for lighting circuits. Is that not the case?

Kind Regards, John