One of the many procedures that go to achieve recognition of “competency” is that of Instrument Ongoing Accuracy.
Even the most experienced of electricians can make mistakes, for this reason, all electrical installations, alterations and additions should be tested, inspected and a certificate issued to the client for use.
The results of the testing must be a true representation of the installation, therefore the test instrument must be accurate and the obtained results must be consistent.
The yearly calibration certificate of an instrument will state that the instrument was within calibration parameters at that time only; it certainly could not guarantee that the instrument would still be fit for purpose at any time after that.
Ongoing accuracy is the checking of an instruments ability to make the same accurate readings throughout the time between these formal calibrations period.
For the prime insulation and continuity installation tests the instruments ongoing accuracy is checked against an identifiable proprietary resistance source of the range expected during testing. These readings should be recorded monthly and be compared against the base readings taken at the time of calibration.
If the values drift +/- 5% then the instrument should be re-calibrated. If the results remain within the ±5% limits then the instrument could feasibly go for a number of years without the need of calibration assessment by a calibration house. For some businesses, this could be a major cost saving.
There are two main electrical working environments Domestic and Commercial;-
Fundamentally in all tradesman’s work, the basic legal precedence, is the fact that - every tradesman and employer has a legal duty of care for the users of their installations.
With the introduction of the Insurance Act 2015 which comes into force in August 2016, insurance companies are placed under a greater pressure to analyse the risks they are being asked to accept. The insurers will access the tradesman based on numerous risk assessments and require a minimum standard by which the contracts must be carried out. Failure to work to these declared standards could result in the insurer using this as a reason to void the policy and avoid the claim completely. Therefore achieving the industry recognised acknowledgment of a “competent tradespersons” may very soon become a major factor on underwriting the contractor’s business.
In the electrical world there are regulations, guidelines, procedures and policies to name a few titles. To administer these there are numerous regulatory bodies that in turn rely upon issued standards such as HSE, building and wiring regulations. This section details a few of these areas and directions for further reading.
DISCLAIMER – This is intended for information only and correct at the time of writing. It is not to be taken as legal advice or authoritative in any respect. For legal or authoritative advice and information please contact one of the regulatory bodies.
These are the standards by which electrical work is governed by and are referred to by all the regulatory bodies. Currently the wiring regulations are in their 17th Edition and are adopted by BSI as BS 7671.
The European standard IEC 60364 is an attempt to harmonize national wiring standards in an IEC standard. BS 7671 follows the section structure of IEC 60364 very closely.
In the UK in 2004 building regulations legally enforced Part P “Requirements for Electrical Installations” which enabled electrical work to be regulated by law.
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Chapter 61 of the 17th Edition makes a new reference to "skilled person (electrically)", which has the added condition of the person being competent in inspection testing and certification work.
The IET in the autumn 2005 issue 16 contained the second article of a series covering testing and inspection.
In particular this article looked at what can go wrong and how to keep track of an instrument’s performance.
Electrical Safety First produces, in association with other industry bodies, a range of Best Practice Guides which provide definitive information and guidance on a range of technical subjects.
Guide 7 covers the Ongoing Accuracy requirements
This general series guidance note is aimed at people (including electricians, electrical contractors, test supervisors, technicians, managers, tradespeople and/ or appliance retailers/repairers etc) who use electrical test equipment on low voltage electrical systems and equipment.
There are many different regulatory bodies associated with the electrical industry. Predominantly they all seek to promote and protect the interests of professional, competent and accountable businesses.
All the bodies are supported by industry technical experts who then provide advice, training and competent assessment services. Inspectors are usually employed to assess the standard of installation work and the capability of individuals and companies as to the level of registration and competence.
NICEIC contractors have a responsibility to ensure the accuracy and consistency of their test instruments used to carry out the range of measurements required by BS 7671 for certification purposes.
You should therefore already have in place an effective system, which enables you to confirm the continuing accuracy and consistency of all your test instruments used for certification and reporting purposes.