How do I find out what is the right MIC for my needs?


I have been told that the Maximum Import Capacity is one of the most important feature of my bill, and that I must ensure it is set at the correct level to avoid paying extra for no reason. How can I check if it could be reduced?


When applying for a grid connection, the most important decision is the capacity level your site requires. The capacity of your connection, often call the Maximum Import Capacity (MIC), is an important figure for several reasons:

  • It is the capacity that the grid operator commits itself to deliver to your premises.
  • It places an upper limit on the total electrical load you can use.
  • It is a determinant for connection charges.

Your MIC may be too high or too low for your needs – either way it will cost you money:

  • If the MIC is too high, you may be paying for more capacity than you require.
  • If the MIC is too low, you may incur an ‘Excess Capacity’ charge.

You must be registered for the capacity that meets your needs, which is generally much lower than the sum of the kilowatt ratings of all the equipment installed.

Example of Apparent Power variations.

It is good practice to measure and review your building’s Apparent Power variations. If your Apparent Power analysis shows that your peak kVA demand for the entire site is far below your registered MIC, you should discuss your MIC with your electrical contractor / consultant. Inappropriate MICs are common (too high or too low), expensive and straightforward to fix. You can also check for Excess Capacity Charges on your bill. If these charges are significant, you should contact your supplier to discuss increasing your MIC.

You can calculate your appropriate MIC by reviewing the contracted MIC and the actual Maximum Demand from your dashboard and your bills over the last year. A best practice recommendation is to calculate the appropriate MIC as:

MIC = (Maximum Demand / 0.95) x 1.1

If your contracted MIC is significantly higher than the appropriate MIC over an extended period and you do not anticipate your MD changing in the near future (extension, expansion etc.), then contact your electricity supplier to discuss a reduced MIC.

Similarly, you may recognise that you need to increase your level of supply if:

  • you add a significant new extension to your premises
  • you begin to use new equipment that requires significant extra power

More on this can be found at [1].