Wiring on Fixed installation with class 5 conductor (Flexible Cable).

Question

Good morning Guys, 
 
 I refer to Chapter 52 ( 521.9) of BS 7671, Can we use class 5 conductor ( multicore Cable) in fixed Installation for wiring lighting, power ? Grateful if someone can help answer with document evidence.

gkenyon · Accepted Answer

Satish Kumar said: I want to ensure that class 05 usage in fixed installation is good by norms. 
 Well, flexible cables (Class 5 and Class 6 stranding) are actually specified for some installations, or parts of installations, within BS 7671. Flexible cables must be acceptable (if properly selected, erected and protected for the installation conditions - as with all cables), because: 
 
 Regulation 422.3.201 permits their use, although has some requirements for their construction or protection. This is supported by Regulation Group 521.9 
 Regulation 413.3.4 has a particular requirement concerning their use in parts of the installation with protective measure double or reinforced insulation. 
 Regulation 418.3.6 for electrical separation to more than one item of equipment requires flexible cables to incorporate a protective conductor 
 They are required to be used for suspended current-using equipment (Regulation 522.7.2) 
 They are required in installations in flexible structures, or where a structures are intended to be moved (Regulation 522.15.2, 
 There are minimum cross-sectional areas for flexible cables "for any other purpose" in Table 52.3 
 Some Part 7 special locations specify certain wiring systems, for which flexible cables are options, or mandated (Regulations Group 704.522.8, Regulation 717.411.3.1.2, Regulation Group 717.52, Regulation 721.521.2 
 
 Of course, when using stranded wires, appropriate terminals ought to be used, or, Class 5 or Class 6 conductors are to be terminated in terminals suitable only for Class 1 (solid) and/or Class 2 (stranded) they should be suitable prepared, for example with a ferrule. (See Regulation Group 526.9.)

Chris Pearson · Answer

I would add to Graham's comprehensive list that an adjustment is made for flexible cables in Table 4D2A , which very clearly applies to fixed installations, be they in conduit in walls, conduit on walls, etc.

gkenyon · Answer

Satish Kumar said: when using stranded wires, appropriate terminals ought to be used, or, Class 5 or Class 6 conductors are to be terminated in terminals suitable only for Class 1 (solid) and/or Class 2 (stranded) they should be suitable prepared, for example with a ferrule. (See Regulation Group 526.9.) 
 This depends on terminal type. to CENELEC standards: 
 
 Terminals that have no marking can be assumed to be suitable for all classes of conductor, although you might want to use ferrules for class 5 and class 6 stranded conductors if they are to be regularly disconnected and reconnected, or where installation and maintenance activities would be slowed down drastically by having to re-strip to reconnect (for example industrial control panels, alarm systems, etc.) 
 Terminals marked 'r' are suitable for rigid conductors (class 1 and class 2 only). Class 5 and Class 6 stranded conductors may be terminated if crimp ferrules can be used (although manufacturer's instructions should be followed for screwless terminals). 
 Terminals marked 'sol' are suitable for class 1 (solid) conductors only. If manufacturers instructions permit, class 2, 5 and 6 conductors might be connected using crimp ferrules. 
 Terminals marked 'f' may only be used for class 5 and class 6 stranded (flexible and extra-flexible respectively) conductors. Ferrules should not be used for Class 5 and Class 6 stranded conductors in terminals marked 'f'

Wiring on Fixed installation with class 5 conductor (Flexible Cable).

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