Hi

In the past our storage warehouse has been receiving electrical inspections every 5 years with the previous electrical company detailing the warehouse as a commercial installation. The new latest survey by a new contractor has detailed the installation is classified as commercial, thus reducing the inspection to 3 years. I've spoke to both contractors with differing views.

I'm under the impression a storage warehouse should be classified as a commercial installation?

Thoughts please............

It's not as cut & dried as that.

Those timescales are merely suggestions from the IET in GN3.
These timescales have made their way into folklore as specific requirements.
They are no such thing.

Firstly, the "person" undertaking the Periodic Inspection, and thus compiling the EICR should from the same source be:
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1.2 Required competence
The inspector carrying out the inspection and testing of any electrical installation must, as appropriate to his or her function, have a sound knowledge and experience relevant to the nature of the installation being inspected and tested, and of BS 7671 and other relevant technical standards. The inspector must also have relevant education and experience to enable him or her to perceive risks and avoid dangers that electricity can create, and be fully versed in the inspection and testing procedures and employ suitable test equipment during the inspection and testing process.

Furthermore, the inspector must employ suitable test equipment during the inspection and testing process and have sufficient inspection experience in interpreting the results with respect to the requirements of BS 7671.

It is worth noting that the person responsible for inspection and testing may be required to formally demonstrate competence by means of registration/certification under a recognised scheme, for example as a condition of contract and/or as a requirement of Area Building Control Bodies.

It is the responsibility of the inspector, as appropriate to either the initial or periodic inspection, to:

(a) ensure no danger occurs to any person or livestock and property is not damaged
(b) compare the inspection and testing results with the design criteria (where available), with BS 7671 and/or previous records, as appropriate
(c) confirm compliance or non-compliance with BS 7671
(d) take a view and report on the condition of the installation.

In the event of a dangerous situation being found, the inspector should recommend the immediate isolation of the defective part. The person ordering the work should be informed, in writing, of this recommendation without delay.
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The "person" undertaking the I&T is free to give any timescale that they see fit according to their Engineering judgement.
Thus they must be competent to make this judgement, and if necessary stand by that in a court of law.

I have given industrial & commercial installations 1 year before now.

I do give 1 day if I consider the installation requires that much work to make it satisfactory, that is my decision & I will stand by that.

SO to the OP, both contractors are right.

Did the latest contractor find "unacceptable" deterioration, "pampering", "non-compliant" repairs or modifications or a "lack of maintenance" which they feel means that the installation should not be left for any more than 3 years before being inspected & tested by a competent person?