Old cable data sheets.

[Gnasher]

Hello

I understand that this may be an impossible one to answer, but I have been surprised on many occasions with what info is out there if you only ask. So here goes.

I am trying to locate historical cable data sheets for paper lead cables that were probably installed in the 1960s

I think that the manufacture was probably BICC who are no longer in existence. I have done a google search and found a company in Cairo who carry the BICC logo. I have emailed them but as yet had no reply.

The cables are imperial 2 core 19/0.64 and 19/1.53 lead sheathed,

The specific info I am looking for is the ohmic values of the conductors and lead sheath. Similar to the Table 11 in the onsite guide R1 + R2 values.

Thanks

Steve

 

[7029 dave]

Would it not be best to get the cable replaced.

 

[Vortigern]

You could work out the resistance

 

[Gnasher]

Would it not be best to get the cable replaced.

Unfortunately that's not an option at the moment. These cables need to be incorporated into an existing system, with designs demonstrating compliance.

All cables have had insulation resistance tests carried out on them and have perfect readings.
The cost would prohibit replacement at the moment.

 

[Gnasher]

You could work out the resistance

Unfortunately I am unable to find resistance values for old imperial conductors. 35mm sq and 95mmsq equivalents.

Additionally I an unable to locate the resistance values of the lead sheath .

One option is to measure the longest length cable and do some maths. Problem is it is not possible to isolate the circuits without a lot of planning and disruption. This will take a few weeks to arrange.

I might be missing something hear if I am please let me know.

 

[Gnasher]

Unfortunately I am unable to find resistance values for old imperial conductors. 35mm sq and 95mmsq equivalents.

Additionally I an unable to locate the resistance values of the lead sheath .

One option is to measure the longest length cable and do some maths. Problem is it is not possible to isolate the circuits without a lot of planning and disruption. This will take a few weeks to arrange.

I might be missing something hear if I am please let me know.

just re-read my reply might sound a bit abrupt. Not intentional.

 

[Lucien Nunes]

I have the original BICC data books (called 'Cables and Tables') which will probably list your specific cables. It might be a few days before I am near the books though, as they are in the museum library.

The conductor resistance can be calculated easily to reasonable accuracy (there will be a minor influence from the layup, drawing tolerance etc.) The sheath will be more difficult as we don't know its CSA but TBH it might not be in the tables anyway. Please can you check the sizes though:

19/.064 (not 19/0.64) is a standard imperial size equal to 39mm². Approx 0.49mΩ per metre of conductor.

19/.153 (not 19/1.53) would be 225mm² so I don't think that's right because you mention 95mm².

IIRC, the nearest 19-strand imperial size for 95mm² would be 19/.103 which is 102mm². Could that be what was meant? If so about 0.18mΩ per metre of conductor.

Would it not be best to get the cable replaced.

Not sure why, if it's sound. Much of the UK still runs on PILC much older than this.

 

[pc1966]

Based on this quick web-search the resistance of lead is about 13 times higher than copper:

Resistivities for common metals

<b>The following table shows the resistivities of several materials. The values are correct at 20 degrees Celsius.</b>

cleanroom.byu.edu

So if you can measure the sheath outer diameter and thickness you ought to be able to compute the equivalent CSA, and from that get an idea of the R2 value to use. However, if Lucian can get you his book values soon enough that would be the best answer.

 

[Gnasher]

I have the original BICC data books (called 'Cables and Tables') which will probably list your specific cables. It might be a few days before I am near the books though, as they are in the museum library.

The conductor resistance can be calculated easily to reasonable accuracy (there will be a minor influence from the layup, drawing tolerance etc.) The sheath will be more difficult as we don't know its CSA but TBH it might not be in the tables anyway. Please can you check the sizes though:

19/.064 (not 19/0.64) is a standard imperial size equal to 39mm². Approx 0.49mΩ per metre of conductor.

19/.153 (not 19/1.53) would be 225mm² so I don't think that's right because you mention 95mm².

IIRC, the nearest 19-strand imperial size for 95mm² would be 19/.103 which is 102mm². Could that be what was meant? If so about 0.18mΩ per metre of conductor.



Not sure why, if it's sound. Much of the UK still runs on PILC much older than this.

Hello Lucien

Thanks for your reply. I never cease to be amazed what info is available if you ask.
More than happy to wait a few days. It will probably take that long to dust the cobwebs off.

You are correct with your observations on the cable sizes. Decimal point in the wrong place.

As you say the sheath may be the difficult one to find out.

Thanks again.

Steve.

 

[Lucien Nunes]

If the cables are currently terminated it might be impossible to establish the sheath thickness by measurement. If ithe resistance or CSA of the lead is not in the book, I guess it will be a case of isolating a good length (hopefully it's on insulated cleats or served) and putting a Ducter on it.

We could probably make a good estimate by weight because the weight per unit length will certainly be tabulated, and copper and lead make up most of the cable weight. Subtracting the known weight per unit length of copper will probably give an answer accurate to 10% for the lead. That could perhaps be tweaked a little by calculating the CSA of paper by subtracting lead and copper from total, and then re-calculating the CSA of lead with the paper weight included. The error will then be reduced by the ratio of (lead density-1) / paper density and probably as close as you would get by measuring a chunk of PILC with a vernier.

 

[7029 dave]

I have the original BICC data books (called 'Cables and Tables') which will probably list your specific cables. It might be a few days before I am near the books though, as they are in the museum library.

The conductor resistance can be calculated easily to reasonable accuracy (there will be a minor influence from the layup, drawing tolerance etc.) The sheath will be more difficult as we don't know its CSA but TBH it might not be in the tables anyway. Please can you check the sizes though:

19/.064 (not 19/0.64) is a standard imperial size equal to 39mm². Approx 0.49mΩ per metre of conductor.

19/.153 (not 19/1.53) would be 225mm² so I don't think that's right because you mention 95mm².

IIRC, the nearest 19-strand imperial size for 95mm² would be 19/.103 which is 102mm². Could that be what was meant? If so about 0.18mΩ per metre of conductor.



Not sure why, if it's sound. Much of the UK still runs on PILC much older than this.

Yeah, did not realize it was MU type cable.

 

[Gnasher]

Based on this quick web-search the resistance of lead is about 13 times higher than copper:

Resistivities for common metals

<b>The following table shows the resistivities of several materials. The values are correct at 20 degrees Celsius.</b>

cleanroom.byu.edu

So if you can measure the sheath outer diameter and thickness you ought to be able to compute the equivalent CSA, and from that get an idea of the R2 value to use. However, if Lucian can get you his book values soon enough that would be the best answer.

Based on this quick web-search the resistance of lead is about 13 times higher than copper:

Resistivities for common metals

<b>The following table shows the resistivities of several materials. The values are correct at 20 degrees Celsius.</b>

cleanroom.byu.edu

So if you can measure the sheath outer diameter and thickness you ought to be able to compute the equivalent CSA, and from that get an idea of the R2 value to use. However, if Lucian can get you his book values soon enough that would be the best answer.

Thanks pc1966

Good suggestion. The outer sheath should be easy enough, the thickness will be a bit more difficult though as the cables are in service.
I can ask if there is an old section about to measure. Fingers crossed.

Steve

 

[Lister1987]

John Ward has CCC sheets for various PILC and MICC if memory serves, night be worth dropping him a bell

 

[Gnasher]

John Ward has CCC sheets for various PILC and MICC if memory serves, night be worth dropping him a bell

Thanks Lister.

How do I contact John.

Steve.

 

[richy3333]

John Ward Flameport Electrical

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