70's wiring in new sockets

[SUNRAY]

The 0.036 was the measurement in thou's of an inch. I don't recall 7.036 ever being referred to as 2.9mm.

It was standard practise to twist the stranded 7.029 and smaller sizes neatly and tightly, to go in a terminal. The solid cores were at first twisted as before, but it was found to be better not to twist. Solid aluminium (there was only ever solid, even the big armoured cables), copper coated (except armoured), was especially brittle and easily damaged by twisting.

Flexible cables are always twisted and formed, to prevent them splaying out.

0.036thou is rather small. It's measured in inches.
Yes individual wires would be twisted and some tried twisting multiples together but that was always a flop. Typically BS1363 accessories would easily take 2x 7/0.029 but to get a 3rd in it was far easier not to twist anything, just 21 strands straight in.

What I pulled out last year included 10mm² ali singles which were stranded.

 

[Harry Bloomfield]

0.036thou is rather small. It's measured in inches.

Think you are correct, measured in 100ths of an inch.

 

[SUNRAY]

The 0.036 was the measurement in thou's of an inch. I don't recall 7.036 ever being referred to as 2.9mm.

It was standard practise to twist the stranded 7.029 and smaller sizes neatly and tightly, to go in a terminal. The solid cores were at first twisted as before, but it was found to be better not to twist. Solid aluminium (there was only ever solid, even the big armoured cables), copper coated (except armoured), was especially brittle and easily damaged by twisting.

Flexible cables are always twisted and formed, to prevent them splaying out.

0.036thou is rather small. It's measured in inches.
Yes individual wires would be twisted and some tried twisting multiples together but that was always a flop. Typically BS1363 accessories would easily take 2x 7/0.029 but to get a 3rd in it was far easier not to twist anything, just 21 strands straight in.

What I pulled out last year included 10mm² ali singles which were stranded.

 

[SUNRAY]

Deleted double post

 

[EFLImpudence]

0.036thou is rather small.

It would be.

It's not 0.036thou(sanths).

It's 0.036 inches or 36 thousanths of an inch.

 

[SUNRAY]

Maybe oxidation? Aluminium exposed to atmosphere delevelops a high resistance oxide coating. Any lugs crimped onto aluminium cables, had to be covered with a special grease prior to crimping, to prevent oxidation. I don't recall the grease being used on aluminium cables where the entered terminals, though I suspect oxidation just as much of a problem in terminals as crimps.

The procedures included different coatings within the joint and to seal it and they were different depending which combinations of metals were involved. The Cu coated Ali bars were treated as copper for making the joints so I'll assume that wasn't the problem.

 

[JohnW2]

In the main we use the appendix 15 plan (BS 7671:2008 regulation 433.1) to see what is permitted, and the lollipop is not show, nor is taking a supply from it with 4 mm² the regulation says ...

There are a lot of possible situations not shown in the limited examples depicted in Appendix 15.

I see no problem with supplying a ring final with lollipop method, using a cooker connection unit for example ...

Nor do I - as I must have reported before, that's exactly what I have in my cellar/workshop - a 'ring final' in the cellar supplied, lollipop-wise, by a re-purposed, no longer needed, (10mm²) cooker supply.

... but not taking a supply from the ring final as you can't ensure power sharing on the two legs of the ring.

As I keep saying, there is nothing wrong, per se, with a 4mm² unfused spur from a ring final which supplies multiple sockets. What one has to avoid is potentially having too high a load being applied to the ring too close to one end of the ring - but that mistake can be made just as easily by putting too many sockets 'on the ring' close to one end of the ring as with having a 4mm² unfused spur originating close to one end of the ring.

There's absolutely no problem with a 4mm² unfused spur (supplying multiple sockets) provided that it originates a reasonable distance from an end of the ring.

Kind Regards, John

 

[winston1]

I don't recall 7.036 ever being referred to as 2.9mm.

Indeed. One reason is because 7/036 is around 4.6mm squared. Another reason is because we were not metric then.

 

[Taylortwocities]

Indeed. One reason is because 7/036 is around 4.6mm squared. Another reason is because we were not metric then.

I’m glad that you mentioned that. And yet we (you included) continue to refer to a lamp size as MR16. That’s an imperial throwback, should we get modern and call it MR50?

 

[Taylortwocities]

...

 

[ericmark]

Indeed. One reason is because 7/036 is around 4.6mm squared. Another reason is because we were not metric then.

I made an error, intended to refer to 7/0.029 at being 2.9 mm² it was a long time ago. 7/0.036 was 4 mm² and 7/0.044 was 6 mm² it was far easier as a simple micrometer would give one the cable size without need for a slide rule as well. Not calculator as did not have one back then.

The MR16 seems to be linked to cathode ray tubes, referring to how many 1/8ths of an inch across. However

should we get modern and call it MR50?

well since most LED lamps don't have the reflector suppose it would be a 50? But it is like the G5.3 I am told since not bayonet there is no U it is only the GU10 where we use the U although not sure about that. But why did we call one after the size of the reflector and other after the connection type?

I remember having to send the crimp pliers away for calibration when working for GEC Large Steam Turbines, and with had orange (1 mm²) and red (1.5 mm²) I seem to remember, separate pliers for each size. No where else I have worked has calibrated crimp pliers, and many places when building a panel it was one terminal for one wire the whole idea of putting three wires in one terminal was really just not done.

I started work as an auto electrician and there were many changes as I moved across including the ratings of cables. Also a lamp was the whole item, order a head lamp and you got everything but the bulb.

 

[crystal ball]

I made an error, intended to refer to 7/0.029 at being 2.9 mm² it was a long time ago. 7/0.036 was 4 mm² and 7/0.044 was 6 mm² it was far easier as a simple micrometer would give one the cable size without need for a slide rule as well. Not calculator as did not have one back then.

The MR16 seems to be linked to cathode ray tubes, referring to how many 1/8ths of an inch across. However
well since most LED lamps don't have the reflector suppose it would be a 50? But it is like the G5.3 I am told since not bayonet there is no U it is only the GU10 where we use the U although not sure about that. But why did we call one after the size of the reflector and other after the connection type?

I remember having to send the crimp pliers away for calibration when working for GEC Large Steam Turbines, and with had orange (1 mm²) and red (1.5 mm²) I seem to remember, separate pliers for each size. No where else I have worked has calibrated crimp pliers, and many places when building a panel it was one terminal for one wire the whole idea of putting three wires in one terminal was really just not done.

I started work as an auto electrician and there were many changes as I moved across including the ratings of cables. Also a lamp was the whole item, order a head lamp and you got everything but the bulb.

MOD (N) requires calibrated crimpers, & I think nuclear industries

 

[winston1]

And yet we (you included) continue to refer to a lamp size as MR16. That’s an imperial throwback, should we get modern and call it MR50?

Perhaps. I imagine (correct me if I am wrong) that MR16 originated in the USA who obstinately refuse to go metric.

 

[Harry Bloomfield]

Not calculator as did not have one back then.

Slide rule.

 

[Taylortwocities]

Log tables