TEBIS from HAGER

There are possibly 2 issues here:

1. The relays may be loaded up to rating; which is always a bad move.

2. All manufacturers of products (except Clipsal as far as I know) take liberties with relay ratings.

More on #2: Relays have a current rating, and this is normally in ac amps, resistive, eg 10A. There is a separate rating for non-resistive loads, eg 6AX, normally for inductive loads, eg motors.

Things like fluoro lamps, CFLs, and now many LED lamps are NOT resistive. Even those with good power factor ratings don't always draw a continuous ac current. For example many CFLs pull a current pulse. So thru the 1/2 cycle they draw nothing, then a big whack of current for a short period.

That's all fine and dandy, it allows a statement of average current draw (which is what you pay $ for) BUT when it comes to breaking that current, a switch off in the middle of the big pulse may exceed the contact ratings of some relays and switches.

This became an issue when ban-the-bulb took off, because a circuit full of CFLs could actually have LESS lamps on it than the same circuit loaded up with incandescent lamps.

So: if the circuits seems to be loaded up close to relay rating, and the loads are CFLs (fluouros not so bad) or possibly even LEDs then it could be that ANY replacement relay will also suffer.

For non-resistive loads, I'd make sure you don't load the relays beyond about 1/2 the nominal / resistive rating.

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Manufacturers of products that contain relays are frequently naive. They don't understand the nature of loads, or of where the weaknesses lie (switch-on=inrush current, switch-off=breaking current). Some loads are worst for switch on, some for switch off.

Simply buying a relay (device) from Tyco or Omron, shoving it on a box with some control gear, and saying "well the Tyco rating is 17A so I'll put 17A on my product" WILL NOT WORK. But products out there do this. The product rating is determined by the relay rating, but the relay rating is not everything. How the product is used is a big deal.

Clipsal actually do understand these issues and have gone to vast amounts of effort to test, model, and control relay (devices) in a manner that should ensure the product does what it says on the can.

HOWEVER given all the above, and the nature of the beast where loads are changed in character to what they were even 5 years ago, I'd still not load beyond 50% of the rating.

Hope this helps.

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NITPICKERS CORNER: There will be some who leap and and down and say "but you idiots should just fix it". Thats naive too. When the nature of loads attached changes, you can't magically make a relay device that changes to accommodate that. Nor can you always just go and easily buy a bigger fatter model from Tyco or whoever. The process of doing all this is long, difficult, involves a lot of specialised knowledge and requires a lot of product test. "Just fix it" avoids the issue that doing so is hard, and doing so after-the-fact is impossible.