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Mains Isolator (MI)

Mains Isolator (MI) 

What is a mains isolator?

It is a device that makes sure that the power demanded by the equipment connected to the installation does not exceed the subscribed power for the supply point.

How does the mains isolator work?

When the equipment connected to the installation demands more power than the subscribed power, the MI “trips” automatically leaving the installation out of service.

To restore service, switch off some of the appliances first in order to lower the connected power below the subscribed power, wait for a couple of minutes, and raise the lever manually.

Where is the mains isolator installed?

If is housed in a standardised sealable box placed on the wall near the door of the house or premises, just before the general control and security panel. It can be attached to the panel, or installed separately.

What are the guidelines regarding the installation of the MI?

Article 10 of Royal Decree 1454/2005 [PDF](*) stipulates that all supplies to consumers must include power control elements according to the installation plans established by the distribution companies and submitted to the regional authorities.

Moreover, as set forth in Additional Provision I of ITC Order 1857/2008 [PDF] (*), pursuant to the aforementioned article, distribution companies must inform the consumers of their obligation to install the equipment and the various possibilities available for its purchase and installation.

For this communication, Iberdrola Distribución Eléctrica will send two notifications to the consumers in its distribution area, the first one informing them of the compulsoriness and requirements for installing the MI; if no reply is received, the second notification will be sent 20 days later, reminding the consumer that, unless it is installed within an additional 20 days, contract billing will be changed automatically until it has been installed.

Additional Provision 2 of Order ITC/1559/2010, dated 11 June, establishes the billing method that will be implemented on 16 June 2010 for those supplies which have received the aforementioned notifications but have not installed the MI within the specified period of time.

What is the first step for installing the mains isolator?

Firstly, it is necessary to check whether the standardised box is placed on the wall, near the general control and security panel. If the box has not been installed, the contract holder must contact an authorised electrician to have it installed correctly. The idea is to have a space separate from the general control and security panel where the mains isolator can be installed.

I already have the standardised box in place. Who installs the mains isolator?

The contract holder has two options:

  • Contact an authorised electrician to have it installed and bear the resulting cost, in which case it will remain the contract holder's property.
  • Ask Iberdrola Distribución Eléctrica to install it and rent it for €0.03/month.   
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In either case, the contract holder must phone Iberdrola Distribución Eléctrica at 900 17 11 71 within the established period of time and inform about the option chosen. Subsequently, personnel authorised by Iberdrola Distribución Eléctrica will check and seal the MI if it has been installed by an authorised electrician, or install it if the contract holder asks Iberdrola Distribución Eléctrica to install it.

In both cases, the contract holder must pay a one-time amount of € 9.044760 + VAT for the checking and sealing work, in accordance with the regulations currently in force.

What happens if the mains isolator is not installed within the specified period of time?

The legislation currently in force stipulates that the distribution companies must increase the bill until the consumer informs that the box or MI has been installed correctly.

Since 1 July 2009, the subscribed power applied to all the affected access rate supply contracts has been 20 kW. (ORDER ITC/1857/2008, dated 26 June, Additional Provision 1) 

Starting on 16 June 2010, as stipulated in Additional Provision 2 of the new Order ITC/1559/2010, dated 11 June, the following will apply:

  • Low-voltage consumers with subscribed power up to 10 kW; in this case there are two situations:
    • Subscribed power up to 5 kW: a subscribed power of 10 kW will be applied for the purposes of billing the corresponding access toll.
    • Subscribed power between 5 kW and 10 kW: a subscribed power of 20 kW will be applied for the purposes of billing the corresponding access toll.
    •   
  • Low-voltage consumers with subscribed power between 10 kW and 15 kW: a subscribed power of 20 kW will be applied for the purposes of billing the toll.
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As of the date of installation of the MI, in accordance with the regulations currently in force, the contract holder will be billed according to the rate and power corresponding to the supply.

 

(*) Spanish Version
  • © 2015 Iberdrola Distribución Eléctrica, S.A. All rights reserved.