Filters.......

[CompostCORNER]

Just wondering really.

Induced AC in my opinion is one of the most underestimated causes for false alarms in your standard domestic system. Not so much with the metal cased end station but with the more lower priced plastic endstation, it's quite common to have an induced AC reading in excess of the 1.2VAC maximum limit. Infact, it's usually uncommon to have a system below the maximum permitted levels. Sure, you could cheat and dump all the spare cores to the earth block, and as I've seen in extreme cases, the tamper circuit linked out and all the tamper legs dumped to the earth block even though the alarm falls outside the regs. Of course, the only real way to ground Induced AC is to add an ACT1313.

Although my present employer under persuasion from us engineers now fits all metal cased endstations to our jobs, my previous employer used almost entirely plastic cased endstations on domestic jobs. Usually Gardtec 370, 570 and 800. He used to charge customers around £50 for fitting ACT1313 and ACT230MSF in the event of Induced AC falsing which lets face it, if added to the price of the pre-installation quote, could have been the difference between getting the job or not.

Ideally, it would be great to fit these filters as standard on the lower priced bread and butter domestic jobs but in the end, due to economics, they were only fitted IF the alarm falsed.

Do any of you fellow engineers or your employers insist fitting of filters on all jobs?

Tony.

[Guest dale]

I admit, I don't tend to fit filters as standard. Mebe I should, but at the end of the day in the domestic market, with such short cable runs I dont tend to see many faults from induced AC - unless some idiot has stuck a cable near mine! Then I just charge the customer to move the cable.

See most homes I do are very straight foreward... there is the endstation, either under the stairs or in the cupboard at the top of the stairs... then seen as all rooms come off the stairs, there is just a wire to every room. Its very rare I have a cable length of more than 10 meters, even for the bell box!

Admitedly on bigger installs I do use the metal end station! But domestic, tend to stick to the plastic option.... mainly cause its cheaper!

Dale