RCD Safety Switch Installation & Testing
NOTE THIS IS ONLY THE QUARTERLY RCD AND FULL RCD TESTING
NOT A FULL EICR REPORT
RCD’s (Safety Switch) trip time / current tests performed on your premises
By having the RCD’s (Safety Switch) trip time / current tests performed on your premises your company will be fulfilling its obligations under BS7671: 2008
RCD Safety Switch Testing
TMUK conducts a 3 monthly, 6 monthly and yearly or bi-yearly procedure (Pending environment) to ensure that the British Standard is being met.
RCD Safety Switch Testing Procedures
Locate switchboard and identify circuits protected by RCD’s
Check switchboard door hinge, locking mechanism and weatherproof seal
Clean outside switchboard and general area
Barcode RCD Circuits for tracking and data management procedure
Push button test to ensure RCD is operational
Plug in RCD test device and measure for trip time and current in accordance with Standard
Record all test results and action taken
To find out more please contact TMUK on 0800 121 8378 or use the online enquiry form below.
H&S Legislation
The Electricity at Work Regulations 1989 specifically deals with electrical “systems” in Regulation 4: (1) All systems shall at all times be of such construction as to prevent, so far as is reasonably
practicable, danger.
(2) As may be necessary to prevent danger, all systems shall be maintained so as to prevent, so far as is reasonably practicable, such danger.
(3) Every work activity, including operation, use and maintenance of a system and work near a system, shall be carried out in such a manner as not to give rise, so far as is reasonably practicable, to danger.
(4) Any equipment provided under these Regulations for the purpose of protecting persons at work on or near electrical equipment shall be suitable for the use for which it is provided, be maintained in a condition suitable for that use, and be properly used.
Regulation 8 deals with Earthing, or other suitable precautions, paragraph 138 of the Memorandum of Guidance on the Electricity at Work Regulations, points out the many accidents caused by metalwork becoming live as a result of faults and high impedance protective conductor connections. It is stated that the danger may be reduced by the use of a Residual Current Device, which is designed to operate rapidly at small leakage currents (typically not exceeding 30mA) but qualifies this by stating that this does not eliminate the risk of shock and should only be used as a second line of defence.
BS7671:2008 Requirements for Electrical Installations (IEE Wiring Regulations 17th Edition) defines the wiring standards for the UK. Installations to this standard are regarded as giving conformity with the relevant parts of EAW 1989. Whilst their use is not mandatory, electricity supply authorities may refuse to connect an installation not conforming to this standard.
Changes in July 2008 to the IEE Wiring Regulations 17th edition increase the need for circuits to be provided with RCD protection. The circuits that require RCDs are as follows:
EGN3 Electrical Guidance Note 3 Residual Current Devices (RCDs)
i. where the earth fault loop impedance is too high to provide the required disconnection time, e.g. where the distributor does not provide an earth – TT systems (IEE 411.5
ii. for socket-outlet circuits in domestic and similar installations (IEE 411.3.3)
iii. for circuits of locations containing a bath or shower (IEE 701.411.3.3)
iv. for circuits supplying mobile equipment not exceeding 32Amps for use outdoors (IEE 411.3.3)
v. for cables without earthed metallic covering installed in walls or partitions at a depth of less than 50mm and not protected by earthed steel conduit or similar (IEE 522.6.7)
vi. for cables without earthed metallic covering installed in walls or partitions with metal parts (excluding screws or nails) and not protected by earthed steel conduit or the like (IEE 522.6.8).
For items ii and vi above the RCDs used should be rated at 30mA.
RCDs may be omitted for:
(a) specific labelled sockets, such as a socket for a freezer. However, the circuit cables must not require RCDs as per v and vi above, that is, circuit cables must be enclosed in earthed steel conduit or have an earthed metal sheath or be at a depth of 50mm in a wall or partition without metal parts.
(b) socket-outlets in industrial and commercial premises where the use of equipment and work on the building fabric and electrical installation is under the supervision of skilled or instructed persons.
As a result almost any changes to circuits may require upgrading of the circuit protection to incorporate an RCD at the supply of the circuit.
Section 531 (IEE Wiring Regulations 17th edition), further defines the requirements for an RCD.
Functional testing is dealt with in 612-13-01( IEE Wiring Regulations 17th edition), which states that for an RCD “the effectiveness of any test facility incorporated in the device shall be verified”.
Maintenance and testing of RCDs
4.3.1 All RCDsaresuitablymaintained,andwhereappropriate,testedbyacompetentperson
4.3.1.1 Guidance on testing of RCDs using Test-buttons
All RCDs have built-in test buttons, which should be used regularly to ensure that the device is working. This button gives a small out-of-balance current of about 2.5 times the normal sensitivity to operate the trip. However, please note that it gives no indication of the time to disconnect the circuit from the supply or the overall safety of the unit.
For units in fixed installations, the built-in ‘test’ button should be operated at intervals of not greater than 3 months, and preferably weekly, to ensure the RCD can trip the supply. A label, in accordance with BS 7671 para 514-12-02, must be fixed at or near to the origin of the supply.
For OB units (which are classed as mobile rather than fixed installations), the RCDs on the supply side should be tested by operating the ‘test’ button at every new connection; and those on the vehicle outlets at least once a month and preferably at every re-location of the vehicle.
For portable units the ‘test’ button should be operated before every use at a new site to ensure that it is functioning. Any device failing to trip must be removed from service (and destroyed / disposed of) immediately.
4.3.1.2 Guidance on full function testing of RCDs
Full function testing must be carried out upon installation and thereafter, at least every five years. This needs to be carried out by a competent person using a proprietary RCD test device. Fixed installations in buildings may be tested by the term contractor for the premises depending on the local arrangements.
The RCD tester will thoroughly test the RCD to the BS Standard as follows :
1) the time taken to operate at the rated current will be measured. This will be carried out with the fault on both the negative half cycle and the positive half cycle. The device must operate within 200ms for RCDs designed to BS4293 and BS7288 or 300ms for RCDs designed to BS61008 and BS610097