Third Party Inspection of Electrical Installation

Carelabs is authorized provider of Electrical Installation’s Study, Analysis, Inspection, and Certification services in UAE, Middle East, Africa & Europe and provide Third Party Inspection of Electrical Installation.

A third-party inspection company is a business organization complying with the ISO 17020 standard. Third party inspection agencies are involved in inspection and testing. In simple words any other agency other than DEWA, SEWA or any other government agency, who conduct inspection, fall under third party inspection category.

An ‘Electrical installation’ according to the IEE Wiring Regulations, is ‘an Assembly of associated electrical equipment to fulfil a specific purpose and having certain Co-ordinated characteristics. Growing concern for public safety and the increasing complexity of today’s fixed electrical installations in domestic, commercial and industrial premises places extra responsibility on electrical test engineers who are charged with verifying conformity to today’s stringent international standard. Thus inspection of installations are done periodically and often nowadays.

Third Party Inspection Procedures are as Follows:

Testing an Electrical Installation

The visual inspection is first carried out to confirm that permanently wired electrical equipment is in compliance with the safety requirements and not visibly damaged, and that fire barriers, protective-, monitoring-, isolating and switching devices, and all relevant documentation are present. After this inspection, electrical testing may commence Other methods are not precluded provided they give equally valid results. Only with the appropriate experience and training, safe clothing, and the right test tools is a person considered competent to test installations. When testing is undertaken it should be ensured that adequate precautions are taken to avoid damage or injury to people, equipment or property, and ensured that unauthorized persons are kept away from danger.

Ring Final Circuit Continuity

The ring final circuit, feeding 13 A sockets, is extremely widely used, both in domestic and in commercial or industrial situations. It is very important that each of the three rings associated with each circuit (phase, neutral and protective conductors) should be continuous and not broken. If this happens, current will not be properly shared by the circuit conductors. Following are the steps for the test.

• Within the distribution board, remove the Line, the Neutral and the Earth conductors from its terminals. Since this is a ring circuit there will be two of each in the same terminal.
• Select the low reading ohm meter function and null the tester.
• Measure between Line to Line to get the reading for r1.
• Measure between Neutral to Neutral to get the reading for rn.
• Measure between Earth and Earth to get the reading for r2.
• Connect the first (outgoing) Line to the second (incoming) Earth and connect the second (incoming) Line to the first (outgoing) Earth (if you cannot see which one is the incoming or the outgoing conductor, just make guess, the testing will show whether you are correct or not).
• Using the low reading ohm meter, test between Line and Earth on every outlet on the ring circuit. The highest reading is the (R1+R2) for the circuit. The readings at each of the sockets wired on the ring should be very similar and the value should be according to this formula: (r1 +r2)/4. Every time the measured value is deviating by more than 0.5 ohms, the connection at the accessory terminals should be investigated.
• Remove the cross connection between the Line and Earth conductors and cross connect the Line and Neutral conductors instead (L1 to N2 and L2 to N1).

Insulation Resistance of Electrical Installation

Insulation integrity is critical to prevent electric shock and fire. It is generally measured between live conductors; and between each live conductor and earth. To measure the insulation resistance between live conductors and earth, the complete installation must be switched off, all lamps removed and all equipment disconnected. All fuses must be left in, circuit breakers closed and final circuit switches closed.

Basically, you’re applying a voltage (specifically a highly regulated, stabilized DC voltage) across a dielectric, measuring the amount of current (leakage current) flowing through that dielectric, and then calculating a resistance measurement. The resistance measurement is in Megohms. You use this resistance measurement to evaluate insulation integrity.

You can use it as:

• A quality control measure at the time a piece of electrical equipment is produced;
• An installation requirement to help ensure specifications are met and to verify proper hookup;
• A periodic preventive maintenance task; and
• A troubleshooting tool.

Connect two leads (positive and negative) across an insulation barrier. After making connections, apply the test voltage for 1 minute.