Sizing csa of old cable

[VWWM 1]

Hi Looking at an old 3036 board and 2 peak and off peak immersion supplies. The cable looks like it is in between a 1.5 and 2.5. It is fused with a 15 amp fusewire. I know some old cabling is imperial but was this a regular thing for a batch of cable in the 70/80s???

 

[Pete999]

Hi Looking at an old 3036 board and 2 peak and off peak immersion supplies. The cable looks like it is in between a 1.5 and 2.5. It is fused with a 15 amp fusewire. I know some old cabling is imperial but was this a regular thing for a batch of cable in the 70/80s???

yep 1/044 and 3/029 for lighting, 3/036 for some loads 7/029 for sockets and ring mains as they were called in those days, cooker 7/044 anything above gets a bi difficult to explain.

 

[Dave OCD]

Further to Petes explanation these cables would have been commonly used up to the 1970s, the 3/036 would be around 2mm in todays metric system and the 7/029 would be around 3mm. [Please correct me if I'm wrong anyone]. I still come across a lot of these cables still in service with stranded and tinned copper conductors and it tests out very well the vast majority of the time. Good old school British quality.

 

[VWWM 1]

Further to Petes explanation these cables would have been commonly used up to the 1970s, the 3/036 would be around 2mm in todays metric system and the 7/029 would be around 3mm. [Please correct me if I'm wrong anyone]. I still come across a lot of these cables still in service with stranded and tinned copper conductors and it tests out very well the vast majority of the time. Good old school British quality.

Looks like it would be the 3/036. What are the cable calcs for these cables?
Are they ok on a 15 amp with a 3kw load usually?
around a 8m-10m cable run, clipped direct and buried in plaster the last 2m.
Thanks for the help.

 

[westward10]

Comparison of imperial & metric conductor sizes

The table in this article show the comparison of imperial and metric conductor sizes in detail

www.daenotes.com

 

[Dave OCD]

Looks like it would be the 3/036. What are the cable calcs for these cables?
Are they ok on a 15 amp with a 3kw load usually?
around a 8m-10m cable run, clipped direct and buried in plaster the last 2m.
Thanks for the help.

Check out the table posted up by Westward 10 Mark, obviously the first number refers to the number of strands in the cables.

 

[VWWM 1]

Comparison of imperial & metric conductor sizes

The table in this article show the comparison of imperial and metric conductor sizes in detail

www.daenotes.com

Thanks Guys. They certainly didnt over spec cable back then.

 

[VWWM 1]

Thanks Guys. They certainly didnt over spec cable back then.

Another question. What is the expected ratio of the live conductors and the cpc's for the ring final? The cpc's for the 7/.029 twin and earth seems a higher end to end than usual, maybe because the lives are a bigger csa as well so they are lower than usual?

Thanks

 

[westward10]

3/.029.

 

[Lucien Nunes]

You mentioned in the OP 1970s/80s. Apart from the beginning of the 1970s, cable installed in this era was metric.

Can you not get into a fitting somewhere to see how many strands the L&N cores have? If it is solid core and bigger than 1.0mm then it is metric. Early 2.5 had a 1.0 cpc... how does that compare with your numbers?

 

[westward10]

You mentioned in the OP 1970s/80s. Apart from the beginning of the 1970s, cable installed in this era was metric.

Can you not get into a fitting somewhere to see how many strands the L&N cores have? If it is solid core and bigger than 1.0mm then it is metric. Early 2.5 had a 1.0 cpc... how does that compare with your numbers?

Very true I skipped over the date if it is correct. My house was built in 1971 and has metric cable with the 2.5s incorporating 1.0 cpcs which could account for the high continuity readings. But if they are imperial the size difference between line and cpc is similar to a 2.5/1.0 cable. With metric the line is ×2.5 larger and imperial ×2.24 larger.
Using the above figures and giving an example continuity reading of 0.50 ohm for your line conductors you should get approximately for the cpcs;
Imperial, 0.50 × 2.24 = 1.12 ohm.
Metric 2.5/1.0, 0.50 × 2.5 = 1.25 ohm.
Metric 2.5/1.5, 0.50 × 1.67 = 0.84 ohm where 1.67 is applied.

 

[VWWM 1]

Very true I skipped over the date if it is correct. My house was built in 1971 and has metric cable with the 2.5s incorporating 1.0 cpcs which could account for the high continuity readings. But if they are imperial the size difference between line and cpc is similar to a 2.5/1.0 cable. With metric the line is ×2.5 larger and imperial ×2.24 larger.
Using the above figures and giving an example continuity reading of 0.50 ohm for your line conductors you should get approximately for the cpcs;
Imperial, 0.50 × 2.24 = 1.12 ohm.
Metric 2.5/1.0, 0.50 × 2.5 = 1.25 ohm.
Metric 2.5/1.5, 0.50 × 1.67 = 0.84 ohm where 1.67 is applied.

I got 0.47 0.47 and 1.36 for my end to ends.

 

[VWWM 1]

Here are a few pics of this old beauty. Thanks Guys all solid cores and stranded 6mm

 

[Pete999]

Here are a few pics of this old beauty. Thanks Guys all solid cores and stranded 6mm

no pics Mate

 

[Lucien Nunes]

all solid cores and stranded 6mm

If the 2.5mm²-size cables are solid it's metric.
1.0mm²-size cables are solid in both metric and imperial (1/.044)
6.0mm²-size cables are stranded both in metric and imperial (7/.044)
but imperial will invariably be tinned and metric plain copper.

If the green/yellow sleeving is original it's probably mid 70's onwards.
The addition is artful.