Oops Jason....have already bought the cable!
Advice required on DIY mains IEC leads for home cinema kit
- Thread starter Stevethetiler
- Start date
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CY cable consists of insulated conductors surrounded by bedding, braiding, outer sheath. CY cable braid is typically steel, 80% coverage.
The cable is typically to VDE 0250 if I recall correctly.
Problem #1 - Running the braid alongside insulated cores in a plug.
It would be wise to at least sleeve the braid to protect the cores.
Problem #2 - CY on building site extension leads failed in the plug.
Repeated flexion of the lead can result in movement of the braid in the plug.
Problem #3 - BS1363 cord clamp is not designed with CY cable in mind.
Not an issue because I suspect the bedding layer would eliminate any chance of the braid eroding cores even with prolonged cable flexion.
Problem #4 - Braid may not be used as a CPC unless CSA is sufficient.
Not an issue as I doubt anyone was planning on 2-core CY (or SY), however it does become one under certain fault conditions.
The key reason about needing to use the proper gland with CY/SY cables is mainly about screening. The screen should be terminated over 360-degrees and proper strain relief provided in a usually high vibration environment. CY/SY cables are invariably used with HVAC or motors.
They key reason why some manufacturers say their CY/SY cables should not be connected "directly to the mains supply" is probably braid CSA. Whilst the braid may not be the CPC, it may become a CPC in a fault condition and remain live because the CSA of the braid is insufficient to blow the fuse. It requires an Adiabatic calculation based on strand number & average strand diameter to verify if it is sufficient to cause the CPD to disconnect the fault. Exactly the same issue over CPD type & rating re BS8436 cable foil. That is why many jump at CY/SY in mains usage.
The cable is typically to VDE 0250 if I recall correctly.
Problem #1 - Running the braid alongside insulated cores in a plug.
It would be wise to at least sleeve the braid to protect the cores.
Problem #2 - CY on building site extension leads failed in the plug.
Repeated flexion of the lead can result in movement of the braid in the plug.
Problem #3 - BS1363 cord clamp is not designed with CY cable in mind.
Not an issue because I suspect the bedding layer would eliminate any chance of the braid eroding cores even with prolonged cable flexion.
Problem #4 - Braid may not be used as a CPC unless CSA is sufficient.
Not an issue as I doubt anyone was planning on 2-core CY (or SY), however it does become one under certain fault conditions.
The key reason about needing to use the proper gland with CY/SY cables is mainly about screening. The screen should be terminated over 360-degrees and proper strain relief provided in a usually high vibration environment. CY/SY cables are invariably used with HVAC or motors.
They key reason why some manufacturers say their CY/SY cables should not be connected "directly to the mains supply" is probably braid CSA. Whilst the braid may not be the CPC, it may become a CPC in a fault condition and remain live because the CSA of the braid is insufficient to blow the fuse. It requires an Adiabatic calculation based on strand number & average strand diameter to verify if it is sufficient to cause the CPD to disconnect the fault. Exactly the same issue over CPD type & rating re BS8436 cable foil. That is why many jump at CY/SY in mains usage.
I've never used CY cable, so I dont know, but SY cable should be terminated into a CX cable gland.
http://www.csedistributors.co.uk/cable/cable-glands/cx-cable-gland.htm
A quick google reveals this:
http://www.csedistributors.co.uk/cable/cable-glands/cy-cable-gland.htm
Jason,
Problem one - yes, the combed out, twisted braid at the plug end is going to have its own earth sleeve with heatshrink covering the point where the braid is twisted.
As for the rest of the problems, the DIY cables are only gonna sit at the back of my hifi etc so flexation is not going to be a problem.
The specific cable im going to use...
http://www.olflex.com.mx/clientes/estructura/img/administrador/archivos/olflex_classic_110_cy.pdf
The braid is already covered with a clear outer sheat which is going to be sripped back at each end to terminate.
One at plug end, with the tinned copper braid twisted and sheathed connected to the earth pin of the plug (correct fuse for appliance fitted)
The other end (IEC c7 and c13) are to be connected as dictates...with the braid being trimmed back and insulated.
As long as these connections are secure and insulated from each other properly, i cant see a problem in using for my intended application.
Any one else think the same or am i barking up the wrong tree??
Problem one - yes, the combed out, twisted braid at the plug end is going to have its own earth sleeve with heatshrink covering the point where the braid is twisted.
As for the rest of the problems, the DIY cables are only gonna sit at the back of my hifi etc so flexation is not going to be a problem.
The specific cable im going to use...
http://www.olflex.com.mx/clientes/estructura/img/administrador/archivos/olflex_classic_110_cy.pdf
The braid is already covered with a clear outer sheat which is going to be sripped back at each end to terminate.
One at plug end, with the tinned copper braid twisted and sheathed connected to the earth pin of the plug (correct fuse for appliance fitted)
The other end (IEC c7 and c13) are to be connected as dictates...with the braid being trimmed back and insulated.
As long as these connections are secure and insulated from each other properly, i cant see a problem in using for my intended application.
Any one else think the same or am i barking up the wrong tree??
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I also appreciate the differences between CY and SY....SY being braided with galvanised steel for armour purposes where the cable would be under high flexation / stress.
Not using this cable as for my purpose, the braid isnt going to be a very good conductor for earth being glavanised steel.
Can anyone answer why the braid on the CY , if its not designed to be earthed, is made of tinned copper - surely a waste of money?
Not using this cable as for my purpose, the braid isnt going to be a very good conductor for earth being glavanised steel.
Can anyone answer why the braid on the CY , if its not designed to be earthed, is made of tinned copper - surely a waste of money?
Correct, SY is steel braid, CY is copper braid.
Would be interesting to do an adiabatic calculation... indeed perhaps someone might have done re choice of 2.5mm meaning larger braid CSA?
Just checking some German Lapp docs for you re "not suitable for connection to the mains supply" or "public electricity supply".
If you use it, make a good job of terminating the braid & sleeving it.
Would be interesting to do an adiabatic calculation... indeed perhaps someone might have done re choice of 2.5mm meaning larger braid CSA?
Just checking some German Lapp docs for you re "not suitable for connection to the mains supply" or "public electricity supply".
If you use it, make a good job of terminating the braid & sleeving it.
As long as i terminate and insulate, use the correct fuses in accordance with the appliance documents - am i corrrect in assuming that this would be accceptable?
The cable that i have on order is the 2.5mm 3 core numbered version, the only problem that i am aware of is physically "fitting" the cores into their respective plugs.
As long s this can be done safely, and from what ive researched, am i correct in saying that using 2.5mm does not pose any problems as opposed to using 1.5mm?
As long s this can be done safely, and from what ive researched, am i correct in saying that using 2.5mm does not pose any problems as opposed to using 1.5mm?
1. I can find nothing re restricting direct connection to public mains.
2. Since CY braid is copper it probably passes the Adiabatic Calculation (for copper k = 115, for steel k = 46).
If you are using a Clipsal IP66 plug...
- Note the strain relief expects quite large outer diameter cable
- Cable like 7.8-8mm is too small despite some docs claiming ok
What size cable have you chosen - it must fit the IEC plug, or are you using the "Wattgate?" IEC connector or such like.
2. Since CY braid is copper it probably passes the Adiabatic Calculation (for copper k = 115, for steel k = 46).
If you are using a Clipsal IP66 plug...
- Note the strain relief expects quite large outer diameter cable
- Cable like 7.8-8mm is too small despite some docs claiming ok
What size cable have you chosen - it must fit the IEC plug, or are you using the "Wattgate?" IEC connector or such like.
I was contemplating wattgate, the diameter of the cable i have chosen accrding to lapp specs is 10.3mm in outer diameter.
The cable itself, (havent decided yet) is likely to have black PET braid over the entire length....this might add to overall diameter but at this point in time, its purely a cosmetic touch........
Outer diameter of Lapp CY 3c 2.5mm is 10.3mm...
- H07RNF 1.5mm is 10.3mm o.d. -- ok fitment into normal plug
- H07RNF 2.5mm is 12.3mm o.d. -- difficult to fit into normal plug
The reason H07 is larger diameter is 07 = 500/700V rated re insulation thickness whereas your CY is only BS6500 flex rated re 300/500V.
Cable CSA of Lapp CY 3c 2.5mm is 2.5mm...
- Most BS1363(/A) plugs are limited to 1.5mm
- Clipsal IP66 BS1363/A plug will certainly take 2.5mm CSA
- MK Inline BS1363/A plug will probably take 2.5mm CSA
The problem may be the IEC end of things.
- Will it take 10.3mm o.d. -- probably if decent quality (Schurter)
- Will it take 2.5mm CSA -- might do, but the braid to consider
Quality of the IEC connector is more important than anything else here, there are some nasty ones as my C19 IEC UPS demonstrated (smoke). Schurter do some good DIY-assembly plugs, check the size limits.
A note to anyone using the Clipsal IP66 BS1363/A plug.
- Most docs specify quite large o.d., some however say 8mm o.d.
- In reality if you use a small 7.9mm o.d. (common flex) it will leak
Colleague with a farm and a lot of pressure washers found this out.
Took a different viton gland insert to get the things sealed, they had cut the moulded plugs off having all MK Masterseal sockets, then changed to Clipsal in order to get a plug which itself could not get water in it when unplugged (farms are good for getting wet smelly anywhere you don't want
- H07RNF 1.5mm is 10.3mm o.d. -- ok fitment into normal plug
- H07RNF 2.5mm is 12.3mm o.d. -- difficult to fit into normal plug
The reason H07 is larger diameter is 07 = 500/700V rated re insulation thickness whereas your CY is only BS6500 flex rated re 300/500V.
Cable CSA of Lapp CY 3c 2.5mm is 2.5mm...
- Most BS1363(/A) plugs are limited to 1.5mm
- Clipsal IP66 BS1363/A plug will certainly take 2.5mm CSA
- MK Inline BS1363/A plug will probably take 2.5mm CSA
The problem may be the IEC end of things.
- Will it take 10.3mm o.d. -- probably if decent quality (Schurter)
- Will it take 2.5mm CSA -- might do, but the braid to consider
Quality of the IEC connector is more important than anything else here, there are some nasty ones as my C19 IEC UPS demonstrated (smoke). Schurter do some good DIY-assembly plugs, check the size limits.
A note to anyone using the Clipsal IP66 BS1363/A plug.
- Most docs specify quite large o.d., some however say 8mm o.d.
- In reality if you use a small 7.9mm o.d. (common flex) it will leak
Colleague with a farm and a lot of pressure washers found this out.
Took a different viton gland insert to get the things sealed, they had cut the moulded plugs off having all MK Masterseal sockets, then changed to Clipsal in order to get a plug which itself could not get water in it when unplugged (farms are good for getting wet smelly anywhere you don't want
Jason, ATM, im intending to terminate with MK toughplug and schurter IEC 320.....also create some leads with fig8 c7 but given the size of the core, i may need to slightly enlarge the entry and provide some strength for the flex.
However, due to only 2 core entry into the c7, i may be able to do this at a push without alteration.
Its a bit of "suck it and see" at this point but as long as i know im on the right path, then im happy to proceed.
Main thing being - its all safe and secure!
However, due to only 2 core entry into the c7, i may be able to do this at a push without alteration.
Its a bit of "suck it and see" at this point but as long as i know im on the right path, then im happy to proceed.
Main thing being - its all safe and secure!
Black PET braid... sigh...
- You would not run the PET braid into the plugs
- Instead use a small ring of adhesive heatshrink to clean the ends off
Using too long a length of adhesive heatshrink will make the cable rigid.
Since no-one can see the CY, I would PET over 1.5mm H07RNF
Avoids Clipsal/MK plug, avoids Wattgate plug... just good quality.
I bet you have not bought a Muffler Bearing for all this? Far better.
- You would not run the PET braid into the plugs
- Instead use a small ring of adhesive heatshrink to clean the ends off
Using too long a length of adhesive heatshrink will make the cable rigid.
Since no-one can see the CY, I would PET over 1.5mm H07RNF
Avoids Clipsal/MK plug, avoids Wattgate plug... just good quality.
I bet you have not bought a Muffler Bearing for all this? Far better.
I wasnt gonna take the PET into either end, just use adhesive heat shrink to secure.....and no, i havent heard of the last thing you mentioned! - tell me more!
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