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.

Don't Forget That Little Green Wire

That simple Green Bonding wire on Fire and Burglar Alarm Cabinets,
it really does nothing and doesn't need
hooked up, right?
WRONG!

by Nick Markowitz, Jr.

A fire alarm system is sounding its trouble signal in a commercial building and the maintenance man has summoned me to check it. He pulls out his ring of keys, inserts them into the lock, then quite suddenly he's unable to move--he is frozen in place.

What exactly has happened here do you suppose?

Well, it's my guess that he's received an electrical shock. Luckily, this time he manages to pull away, but a few seconds more and he could have been toast. So what happened?

It appears the people who installed the fire alarm panel did not do their job properly as they forgot or simply failed to install a small green bonding jumper from the removable panel lid to the back box. This allowed electrical current to flow through the lid when the hot 120 volt wire supplying power to the panel pulled loose, coming in contact with the lid.

Now, had this jumper been bonded from lid to back box, and if the panel had been grounded properly, this event would not have taken place. The breaker would have tripped out and just the trouble signal would have sounded. The problem would have been spotted as soon as the lid was opened. Instead, because the jumper was not used, the maintenance man got a severe jolt.

Grounding and bonding of electrical equipment is critical to assuring that it operates properly. It also assures that any type of overload is cleared. It also assures that if a wire or component disintegrates and touches the metal enclosure in the system, nothing bad will happen to someone working on it.

Now, here's the kicker, not all lids need to be grounded. This is especially true if it is permanently attached to the panel box by means of a full-length piano-type hinge. In this case, code considers the lid properly bonded due to the continual path of metal touching. This is not something you have with a removable lid where only 2 small areas of the lid touch the panel box.

You say "bonding and grounding, what's the difference?"

Bonding is used to eliminate a possible hazard, like with the removable lid. The back box has a ground wire which runs the entire way back to the main service entrance for power. I know it's confusing, but follow the manufacture's guide lines and you'll do just fine. But if you fail to follow them, sooner or later something will fail and there will either be a fire or someone will get shocked.

With electricity it's just like a chain... the weakest link is where the problem will develop.