The new 17th Edition of the wiring regulations is due to be implemented on the 1st June 2008. There are a significant number of changes, additions and deletions, both big and small.By ensuring the manufacturer states the instrument meets this standard and you cannot go far wrong. And of course Megger testers all meet the requirements of the 17th Edition.
The new 17th Edition of the wiring regulations is due to be implemented on the 1st June 2008. There are a significant number of changes, additions and deletions, both big and small.
To align the British and IEC numbering system sections 6 (Special installations or locations) and 7 (Inspection and testing) change places. The new section 7 will now include sections on: “Marinas and similar locations”, “Exhibitions, Shows and Stands”, “Solar Voltaic Power Supply Systems”, “Mobile and transportable units”, “Temporary electrical installations” and “Floor and ceiling heating systems”.
The good news for anyone doing “Testing and Inspection”, - there are no changes that prevent your current Megger testers being used.
A brief summary of current instrument requirements is detailed below:
Insulation testing
The most important change is to the insulation test limits for SELV, PELV and systems of <500 V
| Insulation test voltage range 250 V 500 V 1000 V | New 17th Edition ≥0.5 MΩ ≥1.0 MΩ> ≥1.0 MΩ> | Old 16th Edition ≥0.25 MΩ ≥0.5 MΩ ≥1.0 MΩ |
If a meter has a “built-in” PASS/FAIL indicator for insulation values to the old 16th Edition, the limits must be adjusted to comply with the 17th Edition.
Other instrument requirements have not changed.
Continuity testing
Test current I = =200 mA No change
Test voltage V = 4V to 24V No change
Earth loop testing
Not specified. However a resolution of 0.01O is generally regarded as adequate, to a minimum of 100O for TT installations as defined in note 2 of the new table 41.5 – “Max values of earth fault loop impedance to ensure RCD operation of non-delayed RCDs to BS EN 61008 and BS EN 61009”.
RCD Testing
½ x I, 1 x I at 0° and 180° and 5 x I at 0° and 180°
30 mA, 100 mA, 300 mA and 500 mA.
There are now more references in the 17th Edition to EN 61557, the European Norm for test instruments for use on electrical installations.
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