Feature Test & Measurement
Nathan Barwell of Clare, part of the Seaward Group, explains the implications of the revised Hire Association Europe/Event Hire Association’s Code of Practice (CoP) - providing guidance on electrical safety testing in the hire industry
No compromise on safety H
irers providing tools and equip- ment for use in the workplace have a responsibility under a range of statutory legislation. The updated CoP will assist companies that hire electrical equipment and appliances to the general public or busi- nesses, and recommend good working practices for the management of in-ser- vice electrical equipment for hire com- panies. It also underlines the legal duty of care for operators.
Hire equipment falling within the scope of the CoP includes Class I (acces- sible metal parts) electrical appliances, where the safety of the operator depends on the integrity of one layer of insulation and a grounding conductor which bonds all the metalwork of the equipment to ground thus ensuring that, in the event of a fault in the equipment, any fault cur- rent is diverted to ground and not through the human body.
Class II (double insulated) electrical equipment is where there is no ground- ing connection and the operator’s safety depends on the integrity of two layers of insulation. The first layer is a basic or functional insulation and the second is supplementary or protective insulation. It also covers IT equipment powered by plug and socket, portable and movable equipment, fixed equipment such as cookers, heaters, AC equipment, lumi- naries, as well as 110V equipment.
Reasonable safety steps For any company involved in the hire business or in the servicing of rental equipment, a number of reasonable steps can be taken to ensure the safety of electrical equipment. In the first instance, only electrical equipment from a reputable manufacturer/supplier should be utilised for rental purposes and the equipment should be of a high quality, capable of withstanding ardu- ous usage and hazardous environmen- tal conditions. Items of new equipment should also meet all applicable engi- neering and safety standards. Once a new product is introduced for hire, clearly defined visual inspections must be undertaken before and after the equipment is used. These should range from the cleanliness of the equipment, through to the existence of appropriate operating instructions, safety and warn- ing signs to evidence of damage to the product itself and power cords.
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It is estimated that 90% of all poten- tial defects on portable equipment can be detected by visual inspections. However, the remaining ten percent of undetected faults or defects are poten- tially lethal and in many instances expensive to identify and overcome. As a result, it is imperative that the routine testing of rental equipment is undertaken after hire to detect any possible non-visual defects that may pose a danger to customers during use. For example, a broken ground conti- nuity conductor in a power tool result- ing in the operator providing the path to earth of any fault current and the break- down of insulation which can give rise to potentially dangerous leakage cur- rents, are typical of the types of electri- cal deterioration which might not be discernible by a visual inspection. Manufacturers of new electrical prod- ucts have the ability to access national or international product standards, which outline the type of tests that are appro- priate for different product categories. However, in the hire equipment sector
Right: the CoP recommends that every piece of equipment is inspected and tested after every hire and it is
recommended that it is supplied with proof that it has passed the
required testing
Below: in addition to computerised records it is also recommended that safety testing routines are linked to a tagging or labelling system which accurately defines the status of the hire equipment at any time
the associated risk factors. The revised CoP highlights flash testing (also known as dielectric strength or HiPOT), breaking down testing into two defined types - dielectric withstand voltage test and dielectric breakdown test - this test is not recommended for in service testing and is more commonly used for the manufac- turers type test of the equipment. Dielectric strength testing should only be performed in a safe environ- ment where no hazard will be created. The test voltages applied will exceed 1,000V and the test will be considered a fail if breakdown occurs. Breakdown is assumed to occur when the current in the test circuit exceeds 5mA.
good practice states that a routine flash test should be a required part of the test- ing quality programme undertaken by hire and rental operators, reinforcing the testing undertaken by the manufacturer of the tool during product manufactur- ing and final assembly. Moreover, the CoP recommends that every piece of equipment is inspected and tested after every hire and it is recommended that it is supplied with proof that it has passed the required testing.
This can be achieved through testing electrically powered hire tools for earth continuity, flash test and insulation resis- tance, although a host of other tests such as touch and protective conductor cur- rent, IEC cord or lead tests and RCD trip time tests, may also be required depend- ing on the type of equipment in use and
Testing expertise and recording The CoP highlights that it is important to ensure the personnel who undertake the repair of equipment, which may involve some dismantling or opening up of the equipment, are fully trained in the product they service and are conver- sant with the electrical circuits of the equipment. Irrespective of the repair or testing undertaken, hire shop personnel must be instructed, trained properly and should be continuously updated on safety requirements and safety rules. It’s also essential that a record system is maintained for every inspec- tion and test of every piece of rental equipment - by recording test results and thus becoming aware of any trend towards a failure threshold, or a sudden change in test value, the hirer can anticipate future problems. Many modern testers are capable of storing test results in an internal memory for subsequent error-free downloading to PC-based record pro- grams. The same programs can be used to manage re-test schedules. In addition to computerised records it is also recommended that safety testing routines are linked to a tagging or labelling system. The tags should state details of inspections, tests carried out and repairs undertaken. It should also indicate if the equipment is ready for rental or if the equipment has been withdrawn from rental purposes etc.
Seaward Group
www.seaward-group.com T: 0191 586 3511
Enter 200 JULY/AUGUST 2013 Electrical Engineering
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