SWA Fly lead

[pblec]

spin what is the name of that wire from the MET to DB on a TN S, what is the name of that green and yellow wire that comes from the grey service cut out to the DB on a TNC-S, what is the name of that wire from the sheath on a TN S supply that goes to the MET.

lets safely say i have probably got the terminology wrong, i'm here to learn and improve and i have already posted i may ask some dumb questions but you should know if i'm asking it others are thinking it.

domestic (always asume PME) main earth 16mm, bonding to services 10mm - thats not wrong so even though i may have got some fundemantal terms wrong i had to post that to confirm i do know a little and don't get my sizes wrong just terminology

 

[Deleted member 26818]

From the MET to the DB is the 'main' earthing conductor.
The other two are 'supplier's' earthing conductors.

 

[pblec]

so there you have it i got a term wrong which could've been serious, but as has been pointed out if i used it on site everyone would've corrected my poor terminology.

what about the original question way back 7 pages ago did i get that wrong is it perfectly acceptable to use a metal case as a CPC as has been described.

 

[SimpleSimon]

So why have you listened to Spin in two posts (no offence Spin) and not me in a whole thread? What was I not saying that wasn't getting through? As we established last night, it's fine if you don't know but don't drag out a whole thread pretending when clearly you got your terminology wrong.
I've never disputed you don't know the sizes but the problem is because you got your terminology wrong you don't know the difference between earthing and bonding. And if you do than it's not clearly shown.

 

[telectrix]

the difference is easy to explain. bondage is being tied to the bed. earthing is being handcuffed to a metal bed bolted to the floor.

sorry lads.couln't resist.

 

[Deleted member 26818]

543.2.2 A protective conductor may consist of one or more of the following:
(i) A single core cable (minimum CSA 2.5mm² if mechanically protected, otherwise 4mm²)
(ii) A conductor in a cable
(iii) An insulated or bare conductor in a common enclosure with insulated live conductors (appears to indicate that sleeving is not required when terminating T&E in back boxes etc.)
(iv) A fixed bare or insulated conductor
(v) A metal covering, for example, the sheath, screen or armouring of a cable
(vi) A metal conduit, metallic cable management system or other enclosure or electrically continuous support system for conductors (conduit, trunking, tray or even basket)
(vii) an extraneous-conductive-part complying with Regulation 543.2.6. (Re-bar, RSJ, water pipe or metal casing of a machine or enclosure such as the metal casing of a DB)

The descriptions in brackets are my interpretation.

 

[Amp David]

what size should the fly lead from SWA earth tag to cpc bar be?

If for instance a 6mm SWA is run in should the fly lead be 6mm?

If using the SWA as your CPC, size the flylead as per the CSA of your line conductor.

 

[Deleted member 26818]

If using the SWA as your CPC, size the flylead as per the CSA of your line conductor.

Or use the adiabatic equation (which has probably already been suggested).

 

[SimpleSimon]

Or use the adiabatic equation (which has probably already been suggested).

And the circle is complete. Lol.

 

[Deleted member 26818]

Circles, are just squares without coners.

 

[Amp David]

Or use what evers in the toolbox. What a dragged out thread!

 

[JUD]

From BS 7671 definitions....

Exposed-conductive-part. Conductive part of equipment which can be touched and which is not normally live, but which can become live when basic insulation fails.

The SWA armour is part of the electrical equipment, and so is an exposed-conductive-part. We earth exposed-conductive-parts so that if basic insulation fails enough current will flow to operate the protective device.

Extraneous-conductive-part. A conductive part liable to introduce a potential, generally Earth potential and NOT forming part of the electrical installation.

We bond extraneous-conductive-parts to exposed-conductive-parts so that in the event of a fault everything will be at roughly the same potential and so reduce the risk of electric shock if two parts were touched simultaneously.

 

[pblec]

spin has more posts than you so obviously knows more than you - thats the score on forums isn't it?

sorry guys been away to pick up my son for the hols, i don't know how you cope with that M25

yes i know i got it wrong in my terms i distinctly remember argueing this with a lecturer when i did a 16th course, so you think i would of learned!

 

[Deleted member 9648]

How can a fly lead from an SWA be supplementary bonding?.....I'ts earthing.

I promise I will never ever,ever,ever pull someone up on this again....honest....if I do please have me shot.

 

[IQ Electrical]

I promise I will never ever,ever,ever pull someone up on this again....honest....if I do please have me shot.

Well I can't turn my back on such flagrant flouting of terminology, please don't shoot....