Even if the armour is not used as a CPC it must still be earthed at the supply end. Nothing electrically wrong with more RCDs than necessary (providing they discriminate), price is going to play a large part here I think. If an RCD is being used to provide supplementary protection against direct contact it should not exceed 30mA. Food for thought anyway.
SWA cable, long run how to join
- Thread starter choppachimp
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Big_Spark
Spark, if there is a seperate core in the cable that provides the CPC, then there is no requirement to bond the armouring, in fact Engineers would recommend against it as it introduces a parallel earth path which has the potential to introduce other hazards.
Personally I think this unlikely, but in my experience, where a cable has a seperate earth core, invariably it is due to the fact that the armouring cannot be earthed as the boards used are of the insulating material type..and so whilst the cable is terminated normally, it provides no Earth connection..
Plug..I take your point, and your right, that is why there should be a regulation specifically on this.
Personally I think this unlikely, but in my experience, where a cable has a seperate earth core, invariably it is due to the fact that the armouring cannot be earthed as the boards used are of the insulating material type..and so whilst the cable is terminated normally, it provides no Earth connection..
Plug..I take your point, and your right, that is why there should be a regulation specifically on this.
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A bit late, but a big welcome back to BS!!
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I don't want to stir things (! 
), but why? And which regs are you referring to?
), but why? And which regs are you referring to?
B
Big_Spark
Spark, I hate to say this, but your remembering it wrong..If the cable has an integral earth core, then there is no requirement for the armouring to provide an earth path. The NICEIC technical manual used to recommend that it be connected to Earth regardless, and under the 15th edition it would need to be connected as extraneous metalwork, but under the current Regs this is not the case, although I do agree it would be good practice.
I am not NICEIC and am too young to remember the 15th edition .
I must admit I cannot remember ever installing a SWA cable where the sheath was not connected to earth at least at the supply end. I have just looked up the regulation I was referring to above and it reads as follows:
522-06-03 Except where installed in a conduit or duct which provides equivalent pretection against mechanical damage, a cable buried in the ground shall incorporate an earthed armour or metal sheath or both, suitable for use as a protective conductor, or be of insulated concentric construction......
.I must admit I cannot remember ever installing a SWA cable where the sheath was not connected to earth at least at the supply end. I have just looked up the regulation I was referring to above and it reads as follows:
522-06-03 Except where installed in a conduit or duct which provides equivalent pretection against mechanical damage, a cable buried in the ground shall incorporate an earthed armour or metal sheath or both, suitable for use as a protective conductor, or be of insulated concentric construction......
Obviously by quoting 522-06-03 Spark123 has fully proved he is right and I can not believe that any claimed qualified spark would EVER consider installing an SWA or similar armoured cabled without the armour connected to earth at the supply end, whatever cores they use!!!!!!!!
B
Big_Spark
BJS, I know the Reg, I was speaking in general terms and also of the need to install a cable correctly when buried in the ground..and that means in a duct for mechanical protection..as such the requirements of 522-06-03 do not apply. I do accept though that if you bury the cable as per the requirements, then you will install the cable electrically correctly, if you simply bury it in the ground without a thought to protection, then it is likely it will not be installed electrically correctly...
As I stated in my post, I think it good practice to do this anyway. I have always ensured, where possible, that cables buried in the ground have an integral Earth core and that the armouring is always connected to Earth at BOTH ends. Where an integral Earth is not practicable, then a sperate core is drawn in..but the armouring still connected to Earth.
As I stated in my post, I think it good practice to do this anyway. I have always ensured, where possible, that cables buried in the ground have an integral Earth core and that the armouring is always connected to Earth at BOTH ends. Where an integral Earth is not practicable, then a sperate core is drawn in..but the armouring still connected to Earth.
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