What was the year?

[ericmark]

The loadmaster MCB's I was fitting in 1992 on the building of Sizewell 'B' not on the permanent installation, but for supplies for caravans, huts etc. They were starting to get hard to come by new, but there were so many around and the big advantage was there was a 70 amp version, and the isolator was just same as MCB but with red switch cover and 100A marked on it, so were popular at the time. By 1996 when the Second Seven crossing was being built these seemed to have vanished, I seem to remember not marked type 1, 2, 3, or 4 you had to look up part number and not B, C, D, so think the problem was we did not know the tripping curve. Think that's why we stopped using them.

 

[SUNRAY]

Solid 2.5mm2 single cores for the sockets suggests after circa 1970.

I don't think there was any cable equivalent to 2.5mm2 in the old imperial sizes that was solid, it tended to be stranded. (Obviously smaller imperial cables were or could be solid.)

Others here may be able to confirm if 2.5mm2 imperial equivalent single core was available, before 1970ish.

I think earth sleeving became more commonplace around 1970 too, but the lack of earth sleeving in your board may be down to poor installation. I'm certain it was available then.

Also around 1970 I would estimate there was a growing trend to use more and more PVC round conduit, though this proves nothing.

Possibly people were more inclined to include a seperate cpc in newer metric metal conduits as they were that much larger - I am trying to imagine a metric 20mm metal conduit with just one red and one black in it - they seem lonely in a large conduit with no earth wire. I'm not sure exactly when it became the norm to include a seperate cpc in metal conduit, though I don't think even now we have to.

Again, someone else will have a better idea.

1/0.044" was the largest solid core commonly in use which I'd guess is a bit thinner than 1mm².
1/0.056" at about 1.5mm² was very rare and usually only used for form work such as in control panels.
1/0.063" at about 2mm² was available and I have worked with the stuff but it was rare and hardly ever stocked at wholesalers or mentioned in daily use. Nothing like as nice as 7/0.029" or 2.5mm² to handle. IIRC it was rated at something llike13A despite being the same physical size as 2.5mm² including insulation.
7/0.029" [2.9mm²] was bigger and rated at ~20A.

Sadly a lot of the rarer old sizes no longer appear on cable charts for comparison.

 

[SUNRAY]

To be honest there were so many sizes [theoretically] available that it got very confusing. some sizes became 'fashionable' and the rest dropped into obscurity. I have vague recollections of 0.052" & 0.072 or 0.074" sizes but I suspect these were only for multi stranded use.
The bigger singles sizes like 1/0.083, 1/0.091 & 1/0.103 [I may have 3rd decimal point errors] I've only encountered without insulation.

 

[SUNRAY]

The loadmaster MCB's ... I seem to remember not marked type 1, 2, 3, or 4 you had to look up part number and not B, C, D, so think the problem was we did not know the tripping curve. Think that's why we stopped using them.

Ooo yes I'd forgotten that and not being available in the earlier C50's it caused some confusion.

 

[SUNRAY]

The loadmaster MCB's ... I seem to remember not marked type 1, 2, 3, or 4 you had to look up part number and not B, C, D, so think the problem was we did not know the tripping curve. Think that's why we stopped using them.

Ooo yes I'd forgotten that and not being available in the earlier C50's it caused some confusion.

I'm busting a gut now, wasn't there some confusion on the part number with them? Different info on different lists or something?

It would have been 95/96 we did some work in a nightclub and asked for certain rated supplies for the sound and lighting and we quickly started popping breakers. I think that was the job where we changed the board, much to the disgust of the electricians on the refurb.

 

[Adam_151]

Definatly 70s, maybe even a little earlier than my earlier limit of 75, but not likely to be that much definatly not anytime in the 80s. As someone else as said the lack of earth sleeving suggests that it was still considered optional by the installers, the 2.5mm solid conductors date it after metricification, but in an install like this where its conduit all the way back to the board sugegsts its before the industry realised what a pain 2.5 solid was to go round bends and stranded became the standard, not quite so bad on installes where it was trunking and then a final drop in conduit

 

[RF Lighting]

So today we got some of the floor up and exposed some of the conduit which needs to be removed as it is where the soil pipe will be positioned for a new toilet.

I haven’t proved it yet, but the conduit appears to be imperial judging by the hole on the back of the BESA boxes which look like 2BA, and to my eye the running coupler isn’t M20.

 

[SUNRAY]

So today we got some of the floor up and exposed some of the conduit which needs to be removed as it is where the soil pipe will be positioned for a new toilet.

I haven’t proved it yet, but the conduit appears to be imperial judging by the hole on the back of the BESA boxes which look like 2BA, and to my eye the running coupler isn’t M20.

Didn't they change to m4 screws before metric conduit?

Anyway hadn't we already established the bushes at the CU are imperial?

 

[SUNRAY]

Hang on a minute, did they have round lock rings on imperial tube? I only seem to remember hex or octagonal nuts.