Safety Bulletin Fuse Board Contactors

Contactors are used in modern electrical installations where multiple devices are time switched or when different circuits need to come on at the same time.  For example, storage heaters, external lighting, fan and ventilation control, computer circuits, water heaters etc. These contactors are normally installed in an extension cabinet at the bottom of the fuse board or within the fuse board if it is of an older multi service board type.

It has come to our attention that some of these contactors are being incorrectly installed and are suffering heat damage as shown in the photograph above.

This could lead to premature failure of the unit and the adjacent one. The manufacturers installation instructions state that “In the case of contactor mounting in an enclosure for which the internal temperature is in the range between 50 and 60 degrees centigrade, it is necessary to use a spacer between each contactor”.  We would not expect any boards to reach this temperature but locally there could be hot spots within the boards especially in installations where the contactors are used for high power items such as storage and water heaters. The manufacturers provide 9mm spacers for this purpose.

If you think that your site may have a problem please contact your allocated electrical surveyor/engineer who will be able to inspect the current installation and perform a thermal camera survey and advise as to any remedial action that is required.