Ze & Zs-- unacceptable readings

[telectrix]

it's not exacly mobile homes as in caravans. it's those prefab homes like a large static. but set on bricks. called park homes. and the swa armour is providing the earth

 

[WayneL]

it's not exacly mobile homes as in caravans. it's those prefab homes like a large static. but set on bricks. called park homes. and the swa armour is providing the earth

OK, we'll go with this for now.

The thing I would be more concerned about, rather than the Zs of the 'prefab home' installation(as this is RCD protected), would be this:

How are the services entering the 'home' (extraneous), bonded to the MET.
Bearing in mind that the MET, technically, is at the cut-out.

Unless I'm mistaken, where PME conditions apply, the Main Bonding Conductor has to be sellected in relation to the supply neutral conductor (up-stream of the cutout), and I don't think the armour of 6mm 2-core will suffice - I might be wrong.
It certainly isn't good enough with a resistance of 49.28 ohms.

 

[telectrix]

yuo're right there. i assume that originally it was tns, from MET is 16mm to jubilee clip on SWA, then approx 80m to home where earth taken off SWA. Manweb, or whoever it was called then, converted this mess to PME some years ago. at the moment all i am concerned about is making it safe. will discuss options for improvement once i,ve done the best i can with what's there

 

[WayneL]

It certainly sounds like the jubilee clips might be your main problem - you've got high resistance joints somewhere.......is it not possible for you to gland both ends into an appropriate enclosure.

The 16mm should be alright at the cutout end - you could use same size at 'home' end.

Just need someone to confirm the 'copper equivalent CSA' of 6mm 2-core SWA.

then approx 80m to home where earth taken off SWA.

Does 6mm work out okay for 'volt-drop' over 80 meters?

 

[nick611]

there is a guide that gives swa csa,s.i dont think 6mm will comply.if you tt the supply at meter position you will comply as long as swa csa is 6mm

 

[Sintra]

The copper equivilant is 9.75mm for PVC SWA or 7.07mm for XLPE SWA for 2 core 6mm SWA

 

[nick611]

forgot to say rcd must be 30ma and 40ms at 5 times rating eg 150ma

 

[nick611]

volt drop depends on load current.but 6mm is pretty tight.might sqeeze in on a 32amp mcb

 

[telectrix]

more info tomorrow. her indoors gone to bed!

 

[telectrix]

gone back today, traced back to here. took pic after removing 2 bare 2.5 earths from jubilee clips. fine mess. love the socket directly wired to tails! ripped it all out. TT'd it. got to return to relace twin socket with RCD socket. got rained off

 

[J@mes]

jesus what a freaking mess!!

 

[telectrix]

and we get accused of ripping people off to put things right when the kettle has been working fine for years!

 

[nick611]

ha ha yes never had a problem with it till you turned up!

 

[telectrix]

nick, seen the pic? that is not a problem? nother prob. the 16mm incomer is from the pole cut-out. assumed that the 2 6mm were load side. i terminated the 16mm into an isolator and re-inserted the fuse so as to restore power to the 4 homes i had dissed. wallop! one of the 6mm is now live. caught it with my elbow, OUCH. seems there are 2 feeds into this bag of trticks. made safe when rained off.

 

[Deleted member 9648]

Someone got a genny on the end of one of those 6mm's??