Wednesday, June 30, 2010

Dealing With Antique Fire Panel Power Issues

Due care must be taken when replacing old AC-type fire systems,
including the use of OSHA lock-out, tag-out procedures

Before there was a fire alarm manufacturing company by the name of FireLite, Silent Knight, etc., with panels which incorporated electronic components in them, there where companies known as Faraday, Auth, Autocall, Standard Time, Edwards, etc. These companies produced panels which ran strictly on 120/240 volts AC and used relays and big wire-wound resistors.

These panels made use of two separate power phases to the panel. If the primary phase would go out, the secondary phase would take over and sound a trouble bell or gong. Big, large AC series wired bells or horns were used in the system to sound the alarm. Some where steady while others pulsed a defined code.

These systems, while primitive next to modern panels, where the Cadillac of their day, however. They where built in big, heavy red or silver steel enclosures which contained large pieces of ½ inch or thicker slate, which the components where mounted to. Yes, they are now dinosaurs, but they where built to run forever. However, as technology has changed, so has the fire alarm industry.

These old panels, which used pull stations and heat detectors to activate them and had no smoke detectors or battery back up, have long past there usefulness. And yet there are still many of them out there in apartment buildings and town halls, even some schools.

As codes evolve in coming years these panels will need to be pulled out and replaced. The replacement of these panels carry with it a high risk of danger to technicians who are not familiar with how power was supplied. The problem starts at how they where wired into the 120/230 volt circuit in the building. This is because the small 30 or 60 Amp knife switch boxes that are wired to provide power to the panels are not fused or breaker protected, like normal knife switch boxes.

Fire alarm systems in those days where required to be wired ahead of the main switch gear so that even if the buildings main breaker was pulled, power was always maintained to the fire system. So when a technician pulls the 120 AC wiring out or they go to install 120 AC wiring in the knife switch box they’re dealing with danger should they make contact with the knife switch’s upper lug assembly.

If you will recall, these knife switches are not typically over current protected. Should a technician slip with a screwdriver, it will physically melt and explode instead of tripping the building’s main breaker. This is why only a qualified electrician should remove and remake the 120 volt connection to these knife switch boxes. The alternative is to plug off and abandon them and bring in a new circuit feed that is properly breaker protected.

OSHA lock-out, tag-out procedures must be utilized when working with these old switches because there is always the potential for the switch assembly to not move properly. There’s also the potential that it will not break, which means that 120 volts will continue to be maintained at the panel.

Technicians should carry and know how to properly use UL-Listed Category I or II, 120-volt AC testers, such as a properly used proximity tester or multi-meter to make sure power is fully off when operating one of these old knife switches. In fact, even when electricians and technicians work on modern breaker-controlled panels, they are by law required to follow OSHA Lock-Out, Tag-Out procedures.

If your technicians are not properly trained in the utilization of this procedure, the fines can be substantial should an accident occur. One single violation of OSHA Lock-Out, Tag-Out can result in a fine of $15,000.00!

Alarm companies may think they are exempt from OSHA, but they are just as responsible as a company with a hundred employees. Not even a one-man shop is exempt from these rules. They must understand and be able to fully implement the safety rules and regulations of OSHA or they operate at their own peril.

Yes, these old AC fire systems bring a lot of laughs and nostalgia and the old slate control boards make neat discussion pieces in the den or office, but they can also kill when not properly handled, so follow the rules and you’ll live to laugh another day.

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