What is the Maximum Import Capacity (MIC)?

Each connection point on the electricity network has an MIC associated with it. The network is designed to provide you with an electricity supply that is in accordance with a specified MIC. Business customers agree a level with ESB Networks according to their specific requirements.
It is the upper limit on the total electrical demand you can place on the network system, so it should be high enough to meet the requirements of your business. Capacity is measured in kilovolt-amps (kVA). A kilovolt-amp is similar to a kilowatt (kW).
It is calculated on:

  • the total electrical load installed at your premises
  • the timing of the operation of this load. - it should be high enough to meet the requirements of your business.

Why is MIC important?

When you apply for your electricity connection, it is important to choose the correct capacity for your premises because:

  • This is the capacity of electricity which ESB Networks will commit to delivering to your premises
  • It places an upper limit on the total electrical load you can use.
  • It is a determinant for network connection charges.
  • It forms the basis for the Public Service Obligations (PSO) Levy, which is approved by the CER annually.
  • If your MIC is too high or too low for your needs - it will cost you money:

- If the MIC is too high, you may be paying for more capacity than you actually require.
- If the MIC is too low, you may incur an 'Excess Capacity' charge.

As a general guideline we suggest that your MIC should be set at 5% above your highest electrical load in the past year

**** We strongly advise you to discuss your MIC requirements with your electrical contractor / consultant to determine the correct MIC for your business premises.

How do I estimate my MIC requirements?

It important that you choose the capacity that meets your needs because inappropriate MICs are an unnecessary cost on your business

As a general guide: an appropriate MIC = (Maximum Demand / 0.95) x 1.05.
0.95 is the standard factor to convert kW to kVA, and 1.1 allows a 5% safety factor.

In order to gauge the appropriateness of your MIC you should analyse a full year of electricity usage at your premises – check the actual demand used against your agreed level of MIC

Also check for Excess Capacity Charges on your bill. If these charges are significant, you should consider increasing your MIC.
On the other hand, if your contracted MIC is more than you need then you may be incurring unnecessary MIC charges.
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, change of electrical equipment, etc.), then you can consider a reduction in contracted MIC.
Once the bills have been analysed and the new MIC has been decided in consultation with your electrical contractor / consultant you should fill out an NC3 form located on the ESB networks website to request a new contracted MIC.


Maximum Demand Level (kW): the Maximum Demand charge is the most important feature of your bill for you to check. Your Maximum Demand (MD) is the highest level of electrical demand measured every 15 minutes during the day. To avoid penalty charges, it is critically important that you do not exceed your MD. Try to avoid unnecessary usage during the MD measuring periods of the day. If possible, re-schedule tasks outside MD periods and avoid large loads operating at the same time.

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