Fuse Fail (Fail)

Yesterday I was called out on a service job to one of the worst installs I have seen in a while. What makes it worse is that Jack Fuse Power Port modules were being used! What makes it even worse is that it was an add on to a system that I upgraded relatively recently.

The call came in (late on Friday and my day off!) that several mag locks had no power. To cut a long story short, a company had added three doors to an existing system in an area of a building that previously had only an alarm system. Two of the locks and a keypad were without power.

Eventually after a few red herrings I diagnosed a blown fuse. The problem was caused by the use of a 1A fuse to protect about 1.3A worth of equipment. Along the way I found a litany of other faults and poor practices. I will detail a few.

One of the alarm keypads was connected to fire/lock power. So the blown fuse killed it. I just had to change the link setting on the PP4F to solve the problem. The keypad would have also turned off in the event of a fire trip.

Fire tripped lock power for at least two of the doors was supplied on a single pair in a four core security cable. Four core cable has a low current rating and there was a decent voltage drop present. I had to be mindful that I installed an appropriate fuse to limit current on the cable. To make matters worse RS485 communications were supplied on the same unshielded cable.

The door and reader power was added to a single power supply that is now over loaded. This is a common problem I see during add on installs. Proper thought must be given to power supply and battery capacity. A new unloaded separate power supply was installed but used only to power a single controller and door?? There was not battery or monitoring on the new power supply!

Other problems included multiple faulty inputs that had been shunted in the software to prevent alarm runaways filling up the alarm viewer, substandard cabling that was just laid across the ceiling tiles, at least one door controller not mounted and just hanging by cables, detectors not to client specification, a general rats nest of cables in panels, electrical tape over soldered (or not soldered) joins and items mounted out of level.

It is exactly this type of poor quality install that gives the industry a bad rep and kills confidence of clients/users in their systems.  As far as I can tell this particular install is still under warranty so hopefully the client can get the techs back to fix it all.