Registration.
It is very important to make sure the company you hire is properly registered. A tradesman who has the proper registration is adhering the law and is also one who has undergone the proper training that it takes to become registered. Information about registration can be obtained from the Electrical Contractors Association of New Zealand.

Insurance
The electrical firm should carry liability insurance. This will cover any accidental damage that may occur in your home or workplace, while the work is being undertaken. Ask for proof of insurance and be certain the policy has not lapsed or expired.
Check references.
When you are considering your options, get references from several past customers. Check the references by calling the referees to ask about their personal experiences working with the specific electrical firm. Find out if the job was done within the budget and on time.
Get an estimate on your electrical job.
Once you have thoroughly checked out the company’s level of experience, registration, insurance and references and they have passed all of the checks, it is time to ask for a written estimate. It is a good idea to get several quotes so that you can compare several different firms on price as well as other characteristics that are important to you.
Cheaper is not always better.
As the old saying goes, you usually get what you pay for. Your goal should not be to find the cheapest price. Instead, you want an experienced contractor who also charges a reasonable fee. Very cheap prices, in fact, could be a red flag that indicates the a tradesman may cut corners and not do quality work, in order to charge very low rates.
Make sure the proper permits are obtained.
An experienced electrical business will be familiar with what permits are necessary and handle all of the details. Just make sure this is included in the job specification you are hiring the company for.

Availability.
Availability is very important when it comes to making your decision. You also need a professional who will be available once the work is complete, just in case a problem comes up. For longer projects, you will also want a work schedule, so that you will know the duration of the project and have a good estimate of when the project will be complete.