I've pated this in the FAQ but dont see it there. Here's the whole thing (includes handy refs to BS7671 too!) enjoy:
SCHEDULE OF INSPECTIONS
Method of protection against electric
shock
Item inspected Brief Explanation and Example
a) Protection Against Both Direct or Indirect Contact
1. SELV 411-02
IT & C Book 4th edition (page 155) Eg, a Safety isolating transformer having no connection to earth on secondary side. Output of such a transformer provides an output of no more than 50v AC (BS 60742).Eg a transformer used with SELV downlights
Above 25 V AC insulation of conductors or IP2X barrier required.
A generator in which windings provide electrical separation to BS60742, or BS3535(obsolescent)
An electrical chemical source e.g. battery.
2. Limitation of Discharge of Energy
411-04 (Page 155) An electrical fence controller controlling an electric fence. Output current is limited to safe level of energy. Contact with electric fence is painful, but energy contained in discharge is not of a level to be dangerous to person or livestock.
b) Protection Against Direct Contact
3. Insulation of Live Parts
412-02 (Page 156) Insulation of live parts in Service – e.g. Cable Insulation
4. Barriers of Enclosures
412-03 (Page 156) Barriers or enclosures(distribution board, junction box) must have:
• Minimum of IP2X (Finger Test of 12.5mm)Blank plates in DB`S
• IP4X on horizontal surface (1mm strand)
e.g. grommets and blanks in place.
5. Obstacles
412-04 (Page 157) e.g. Obstacle can be a set of railings a minimum of 1.25m from live parts to prevent accidental contact with live parts.
Can only be used when access is restricted to skilled persons.
6. Placing Out of Reach
412-05 (Page 157) The live part out of reach must be a minimum of 2.5m above floor. Can only be used when access is restricted to skilled persons.
Eg an overhead line,an overhead electric crane
7. PELV
471-14 (Page 159) Similar to an SELV System except the ELV circuit is connected to earth at one point with primary circuit.
Not suitable to be used when SELV System has been specified.
8. Presence of RCD for Supplementary Protection
412-06, 471-16-01 (Page 159) Socket outlets rated at 32A or less which may reasonably be expected to supply portable equipment for use outdoors must be protected by an RCD rated at 30mA or less.(The person is now standing on true earth). This is the x5 test. Maximum tripping time of RCD is 40ms
c) Protection Against Indirect Contact (Including EEBAD) EEBAD = Earthed equipotential bonding and automatic disconnection of supply
9. Presence of Earthing Conductor
542-03 (Page 161) Protective conductor which connects main earthing terminal of the installation to the means of earthing. A visual check must confirm earthing conductor is the minimum required in Section 543, and where PME conditions apply 547-02-01
10. Presence of Circuit Protective Conductors
543-01 (Page 163) CPC’s must be checked to ensure they have been correctly sized and installed to Table 54G.or use of adiabatic equation
11. Presence of Main Equipotential Bonding Conductors
547-02 (Page 163-165) Bonding Conductors connecting the main earth terminal of the installation to extraneous conductive points e.g.
Water Service Pipe
Gas Service Pipe
Lightning Protection System
If TNCS earthing arrangement, check with table 54H
If TNS system, cable is half csa of the earthing conductor for the installation. Minimum size is 6mm,maximum size is 25mm
12. Presence of Supplementary Equipotential Bonding Conductors
547-03 Generally applicable only to installations where there is increased risk of shock. Some of these are in Section 6 of BS7671 e.g. bathrooms, swimming pools, saunas, farms. Minimum of 2.5mm if mechanical protection,4mm if not.
No need to bond plastic pipes
13. Presence of Earthing Arrangements for combined protection and functional purposes
Section 546 (Page 166) Protective arrangement always takes priority after functional.
A functional earth is one which is required to make equipment function e.g. Telecom equipment, high integrity earthing(section 607)3.5mA leakage current for item or 10mA for circuit.
Where an earth is for functional purposes only The cable sheath is coloured cream.
For combined protective and functional purposes cable sheath is green/yellow.
14. Presence of Adequate Arrangements for Alternative Source Where Applicable
Section 551 (Page 166) Check for the appropriate isolation, manual and automatic switching of generators, UPS etc.
e.g. those used for parallel and standby sources.
15. Presence of Residual Current Devices
531-02 (Page 166) An RCD is required in any circuit where the earth fault loop independence is too high for protection against indirect contact by other means. E.g. ELI measured exceeds max value in table 41B2 for an MCB(or 80% in NICEIC tables)
This is x1 Test for 30mA RCDS in a TT System. ZS x I^N < 50V given in regulation 413-02-16. This formula is modified to < 25V in special installations and locations(eg construction sites, agricultural premises)
16. Use of Class II Equipment or Relevant Insulation
413-03 (Page 166) Class II equipment is double insulated and generally applicable only to individual items of equipment e.g. luminaire, space heater etc. Regulations 413-03-03 to 09 and 471-09-01 to –4 should be checked to ensure the equipment complies.
17. Non Conductive Location. Absence of Protective Conductors
413-04 and 471-10 Not recognised in relations for common use. Reliance is placed on provision of insulating walls and floors and the separation by more than 2 metres of 2 exposed conductive parts, or an exposed conductive part or any extraneous conductive part e.g. a test room.
Sometimes used overseas
18. Earth Free Equipotential Bonding Presence of Earth Free Equipotential Bonding
471-11, 413-05, 514-15-02 (Page 167) Not recognised in regulations for common use.
All exposed conductive parts and extraneous conductive parts which might be accessible at any one time should be bonded together by an equipotential conductor which itself must not be in contact with earth.Correct application results in a faraday cage
It must be ensured that in the event of basic insulation failure all exposed metal work are at same potential.
This system is only likely to occur in an industrial testing situation.(eg specialist electronic w/s)Normally used with electrical separation
19. Electrical Separation
413-06, 471-12, (Pages 167-168) Applied to a single item of equipment such as a shaver unit to BS3052, a safety isolation transformer to BS3535 or a motor generator having separate windings
d) Prevention of Mutual Detrimental Influences
20. Proximity of Non Electrical Services
528-02 (Page 169) Check that any heat, steam, smoke fumes or condensation is not likely to damage the electrical installation, or that electrolytic corrosion is not likely to occur between dissimilar metal parts of the electrical installation and building structure.
21. Segregation of Band I and Band II Circuits or Band II Insulation Used 528-01 (Page 170) Band I circuits are telecoms, bell, control and alarm installations operating below 50V AC and 120V DC.
Band II circuits are LV circuits not exceeding 1000V AC or 1500V DC between conductors or 600V AC or 900V DC between conductors and earth. Where Band I and Band II circuits are contained within a common system, insulation must be to Band II system.
22. Segregation of Safety Circuits
528-01 (Page 171)515-02-01 and 515-02-02
Fire alarm and emergency lighting circuits are required to be segregated from other circuits and from each other in accordance with BS5266 and BS5839. This means a separation distance of not less than 300mm,by separate enclosures, separate trunking or compartment or by wiring each circuit in MICC cable.
BS5839 Part 1 (2002) and BS5266 Part 1 (1999) should be consulted.
e Identification
23. Presence of Diagrams, instructions, circuit charts and similar information
514.00 (Page 172) For a domestic electrical installation a copy of the completed circuit schedule will suffice.
In larger installations all necessary diagrams, circuit charts or tables should be provided at or adjacent to each DB.
This information is invaluable when carrying out PIRS at a later date.
24. Presence of danger notices and other warning notices
514-10 to 514-13 (Pages 172-174) e.g. voltage warning label if voltage exceeds 230v
Isolation label
Periodic inspection label
RCD label
Non standard colours
High protective conductor currents.
25. Labelling of protective devices, switches or terminals
514-01 (Pages 174-175) All fuses, circuit breakers, RCDS within a DB should be arranged so they correspond with circuit charts. Isolators should be labelled so there is no possibility of confusion.
All connections of live, neutral or CPCS should be identified by arrangements and relate specifically to outgoing fuse or circuit breaker by Sequence e.g. 1,2,3 or 1L1, 1L2, 1L3
26. Identification of conductors
514-03 (pages 175-179)
This is extremely important especially since the introduction of the harmonised cable colours. Every core of a cable must be identified by colour and/or lettering and/or numbering at its termination. Where older installations are interfaced with new a ‘Caution’ label must be provided at the appropriate DB or consumer unit.
f Cables and conductors
27. Routing of cables in prescribed zones
or within mechanical protection
522-06 (pages 180-181)
Zones are as follows:
• Within 150mm from top of wall or partition
• Within 150mm of an angle formed by two adjoining walls or partitions
• Running either horizontally or vertically to a point, accessory or switchgear on the wall or partition, containing a cable connected to the point, accessory or switchgear
• Zone extends to the reverse side of the wall or partition of 100mm thickness or less if the location of the point, accessory or switchgear can be determined from that reverse side (522-06-06 and 2 2004) Cables concealed in the fabric of a building at a depth of 50mm or less from the surface of a wall must be checked they are routed within the prescribed zones. Provided the cables are routed within the zones they do not require an earthed metal covering, be of insulated concentric construction, enclosed in an earthed metal enclosure or mechanical protection.
Zoning Within a Floor or Ceiling
Where a cable is installed under a floor or above a ceiling it must be run in such a position that is not liable to damage by fixings. Where the cable passes through a timber joint or batten etc, it must be at least 50mm from top or bottom as appropriate (measured vertically) of the timber member, or joist/or batten.
28. Connection of Conductors
526-01 to 52-03 (Pages 182-183)
Every connection between conductors and equipment must be mechanically and electronically sound. Insulation must be undamaged. Method of connection should take account of external influences e.g. moisture, vibration and thermal cycling. Connections should remain accessible apart from compound filled joints, cold tails,welding,soldering,brazing,
Or compression tool.
Every joint or connection in a live or PEN conductor must be made in an enclosure complying with Reg. 526-03. This also applies to ELV circuits.
29. Erection Methods
521-01 to 529-01 (Page 183)
Compliance with requirements of Chapter 52 must be met at each stage of construction to confirm all equipment and materials comply with the appropriate BS or equivalent.
Matters to be checked are: cables and conduits adequately supported, accessories and switchgear securely fixed, bending radii of cables is not exceeded.
Single cables of AC circuits run in steel conduit or other form of ferrous enclosure shall be installed to avoid individual cables being surrounded by ferrous material thus negating electromagnetic effects (521-02-01
30. Selection of Conductors for Current Carrying Capacity and Volt drop
Page 184)
Sizes and types of all installed cables and conductors of any busbar system should be checked against the installation design information to check they have been selected and installed as intended by the designer.
g General
31. Presence of fire barriers, suitable seals and protection against thermal effects
422-01, 527-01-02 (page 185)
Where the wiring system passes through an element of building having a specified fire resistance. The space around the wiring system must be sealed to the same degree as the building element. Similarly where a wiring system has an internal space e.g. trunking passing through a fire barrier, the wiring system must also be sealed internally. The exception to this is a non flame propagating wiring system with an internal CSA of not more than >710mm2 (32mm diameter) need not be sealed.
Protection against thermal effects such as hot surfaces near to electrical equipment must be checked e.g. boilers, heaters, lights etc.
32. Presence and correct location of appropriate devices for isolation and switching
537-01 (Pages 186-190)
The inspector should check the installation against design information to check all devices are present and correctly located. Isolation and switching is a global term used to cover four functions.
Isolation
Switching for Mechnical Maintenance
Emergency Switching
Functional
Isolation – Mainswitch at origin to switch. supply on load. Other isolators will be used down stream. As a rule of thumb contact distance is 3mm.
Mechanical Maintenance – e.g. switch or socket outlet, fan isolator. Unless the device is under continuous control of the person carrying out maintenance then it should be locked off. Unintentional reclosure shall not be possible
Emergency Switching – e.g. an emergency stop push button in a workshop.
Certain parts of a machine may remain live for safety e.g. vacuum pumps. BS7671 forbids the use of plug and socket arrangements. Switches or push buttons are normally coloured red.
Functional Switching – functional switching is required for any circuit or part of that requires independent control e.g. switches, plugs and sockets up to 16A. Off-load isolators, fuses or links must not be used for Functional Switching.
33. Adequacy of access to switchgear and other equipment
513-01 (Page 190)
It must be confirmed that adequate and safe means of access and working space has been afforded to all equipment.(eg,can I open the door) For open type switchboards (not commonly encountered) EAWR advices for LV applications, the working space for open type equipment is 2.1m above and a clear width from bare conductor of not less than 0.9m.
34. Particular protective measures for special installations and locations
600-01 (Page 191)
This refers to those areas where risks of electric shock are increased due to wetness, absence of or minimum clothing, presence of earthed metal, arduous conditions and where risk of fire may also be increased. Examples of this are:
Bathrooms and shower rooms
Agricultural premises
Swimming pools
Construction sites
Particular protective measures may be the use of a 30mA RCD, supplementary bonding, reduced fault clearance times.
Part 6 of BS7671 identifies some but not all special locations.
35. Connection of since pole devices for protection or switching in phase conductors only
464-01 (Page 191)
This is a visual check to verify all single pole devices are connected to the phase conductor only. No single pole ‘Switching Device’, circuit breaker, fuse or solid link which can be removed without the use of a tool should interrupt or control the neutral conductor.
This test should be carried out in addition to the polarity checks.
36. Correct connection of accessories and equipment
526-01 (page 191)
The installation should be examined to verify that conductors at accessories and other items of equipment are both electrically and mechanically secure.
37. Presence of undervoltage protective devices
451-01 (page 193)
These devices are found in starter units controlling and protecting motors. They may also be found in heating contactors and automatic control systems to bring in standby generators. The presence of any devices to prevent automatic reclosure of undervoltage devices must also be checked (i.e. sudden restarting of a machine).
38. Choice and setting of protective and monitoring devices (for protection against direct and indirect contact and/or over current)
531-01 to 533-01 (Page 193)
This item is concerned with fuses, circuit breakers, RCDS and any current monitoring relay which control circuit breakers.
For fuses and circuit breakers, check BS No. type and rating.
For MCCBS check current setting, time/current characteristics against design.
For monitoring relays check ratings against de
39. Selection of equipment and protective measures appropriate to external influences
522-01 to 522-12 (Page 194)
Examples of external influences are ambient temperature, impact, vibration, water, high humidity, solid foreign bodies.
Examples of protective measures are a standard DB housed in an DP 54 enclosure in a sawmill, an IP 67 luminaire in a swimming pool.
40. Selection of appropriate functional switching devices
637-05 (Page 194)
This item was covered in item 32 of the Schedule and simply requires all or part of a circuit to be controlled independently e.g. a light switch.
