What is important to watch out for during this inspection of electrical installations
In general, Guidelines for visual inspection of electrical installations with regard to the safety of persons, the age of the parts, deterioration, corrosion, and overloading of the equipment.
Adequacy and influence external to the power system should also be included. At this point, it is a good idea to obtain from the customer any documentation relevant to the installation (plans, drawings, results of previous tests and certification / if applicable, fuse tables, etc.).
You should also clarify that you will require access to all parts of the building and that the electricity supply will need to be cut off at some point. It is also a good idea to ask the customer if they are aware of any changes that have been made, as this information may be useful to you during the inspection.
The visual inspection of any installation is as important as any test performed on an installation; If you are unfamiliar with the building, this is also a good opportunity to orient yourself first.
The first part of the visual inspection is to verify that the system is safe to test and that you have enough information to be able to perform the test safely.
Generally, a good place to start would be consumption. this will give a reasonable indication of the age, type and size of the installation.
Checking the intake
Things to look for in the intake supply before removing any cover would be:
- The type of power system – is it TT, TNS, or TNCS?
- Are the drivers imperial or metric?
- What kind of protection is there for the final circuits?
- Is Documentation Available For The Original Installation? (Very important!)
- Is the consumer unit correctly labeled?
- Is the grounding conductor in place?
- What is the size of the earth conductor?
- Is the protective conductor green or green and yellow?
- Are all circuits in one consumer unit or are there two or three units that need to be combined?
- Is there any evidence of equipotential bonding? Remember! It must start with the main earth terminal.
- What is the size of the equipotential bonding? Is it big enough?
- Is there a residual current device (RCD)? If so does it have a tag attached? Is it a type of voltage or current?
- Do the enclosures meet the required IP codes? (By-law 412-03-01)
- If changes have been made, is there documentation available to them as well as the test results?
- What is the size of the power fuse? Is it large enough for the required load?
- Are the meter tails big enough?
- Are the seals broken on the supplied equipment? If they are, it may indicate that the system has been tampered with since it was first installed and may require further investigation.
- Have any changes or additions been made?
- Would any changes or additions affect the disconnection time required for the affected circuit?
This list is not exhaustive and installation conditions may require more. When the visual inspection of the feed area is complete, it is a good time to take a look around to make sure there are no obvious faults.
All of this should be done before all covers are removed.
Things to look for:
- Are the accessories securely attached to the wall? Are they missing or damaged?
- Are the props old with wooden backplates?
- Are the outlets round or square? Is there a mixture of the two?
- Have cables been installed in vulnerable situations?
- Have cables, housings and accessories been properly secured?
- Do ceiling roses have stray arrows? (Special attention should be given to old braided and rubber cables.)
- Are there outlets that can be used outdoors? If they are, they should be protected by the RCD. If they were installed before the late 90s, it is not mandatory to install them, but an RCD should be listed as a recommendation.
- Do the grounding clamps conform to BS 951 and correctly labeled?
- If the gas is bonded to water using the same conductor, make sure the conductor is continuous and not cut at the clamp.
- Is the additional bond in place in the bathroom?
- Is the right equipment for the right areas in the bathroom / shower? (See 601 BS 7671)
- Did the room have a shower installed? If so, are the outlets 3 meters from the shower and the differential protected?
- Is there any evidence of mutual prejudice influence; Are there any cables attached to water, gas or any other non-electrical service? (Cables should be far enough apart to avoid damage if non-electrical work is performed.)
- Are the cables of different voltage bands separated? Telephone cables or separate low-voltage, extra-low-voltage (SELV) television antennas should not be fastened together (although they are allowed to cross each other).
While checking these items, look in cabinets for outlets or lamps. If your customer is uncomfortable with this, it is vitally important that you document any areas that you cannot investigate in the Scope and Limitations section of the Periodic Inspection Report.
During this purely visual part of the inspection you will get an idea of the condition of the installation, as well as any modifications made by a qualified trader or by a cowboy / girl.
Clearly, if this is an old installation, an electrical installation certificate must be completed and some of the items listed above will apply. However, if this is a new installation, access to all areas must be secured; if this is not possible, the certificate should not be issued. Again, this list is not exhaustive, but will not require the removal of fittings etc.
If you are sure that the installation is secure, a more detailed visual inspection of electrical installations can be performed and the dreaded but necessary form filling can be started.
Again start at the consumer unit. Before you start, this needs to be isolated. The Electricity at Work Regulations 1989 makes it an offense to work alive. Once you remove a blanket, you’ll be working live if you don’t insulate it first.
After the safe isolation procedure has been completed, remove the cover from the consumer unit.
- Your first impression will be important – has the cable terminations been taken care of (clean conductor and not too exposed)?
- Are all cables terminated and all connections tight (no loose ends)?
- Are there signs of overheating?
- Is there a mix of protective devices?
- Are there rubber cables?
- Are there any damaged cables (dead or cut)?
- Do all circuits have Circuit Protective Conductors (CPCs)?
- Are all grounding conductors sheathed?
- On a photocopy of a test results calendar, note the circuits, protective devices, and wire sizes.
- Look to see if the guards seem to fit the size cables they are protecting.
- Note any Type D or Type 4 circuit breakers – these will require further investigation.
- Are all the obstacles in place?
- Have all the conductors in the circuit been connected in sequence with phase, neutral, and CPC of circuit # 1 being at terminal number 1 – preferably the highest current closest to the main switch?
- Do protective devices have multiple conductors, are they the correct size (all identical)?
- Is there only one set of tails or was another card connected to the original card when joining the terminals?