1. Copper can not be buried direct in concrete.
- Concrete will attack copper quite aggressively & perforate
- Not uncommon with u/f GCH copper pipes run in the screed - wet floor
Solutions
- Run copper in plastic conduit
- Use PVC coated copper pipe, white for water, yellow for gas
-
www.bes.co.uk www.b-e-s.co.uk should list it in various sizes
PVC must be continuous over the entire length in concrete, ie, you can not "just a bit of copper touching concrete where it enters the floor". That is more likely to corrode quickly due to environmental & cleaning product interaction over time.
2. Terminating SWA...
- Remember the drip loop AND a repair loop if possible
- Repair loop is so you do not need to joint/replace if end damaged
You can buy SWA cutters for 25 notes or so.
Alternatively rotary pipe cutter to cut sheath, then score the armour half way, snap the armour. The bedding should extend slightly beyond the brass gland (if only because the gland is often sharp and the bedding can be as little as 0.5mm thick for certain sizes). CW glands for outside or anywhere which might get excessively damp (plastic corrugated shed roof).
I much prefer an Earthing Nut or Piranha Nut than Locknut - more professional, use set screw to lock-in place, pozidrive screw with yellow ratchet crimped CPC.
SWA cable cleats can be fitted by screws into wallplugs, or the nail type into smaller wallplugs (they will otherwise rip most mortar apart & fail).
Practice terminating SWA if unsure, not difficult. The armour wires should be the right length to go under the ferrule and butt against the gland. The armour wires should all be the same length (hence the rotary pipe cutter). The armour wires should not extend much beyond the cone of the front gland, just enough to permit assembly and never hang out the bottom. The back gland on the CW glands is the IP68 part (rubber seal), the front gland is the armour termination on both BW & CW glands.
You can put a little lubrication on the front gland threads to ease assembly, because the armour wires bite against the hatched coned section for earth continuity. If not happy, dissassemble, see where you went wrong and correct.
CMP are decent glands, there are others, but beware some are well crap - undersized body, gland component threads miss-tapered and strip with the slightest provocation.
3. Pipe separation from cables.
From IEE regs...
"Electrical and all other services must be protected from any
harmful mutual effects foreseen as likely under conditions of
normal service. For example, cables should not be run in contact
with or run alongside hot pipes." (OSG p55, 528-02-02)
From Gas regs...
BS6891-2005 8.16.2 Separation of installation pipework from other services
Where installation pipes are NOT SEPARATED BY ELECTRICAL INSULATING MATERIAL, they shall be spaced as follows: a) at least 150 mm away from electricity meters and associated excess current controls, electrical SWITCHES or SOCKETS, distribution boards or consumer units; b) at least 25mm away from electricity supply and DISTRIBUTION cables.
From Plumbers regs...
No idea if plumbers have a reg, may well copy gas regs.
You are running the cable in a separate duct or conduit - which is fine if that is electrically insulating material (flex or rigid conduit to a recognised BS which is anything from a sparks-factor), complies with all the above.
