Lightning Protection


I've read on other posts that a whole house arrestor is the best protection against damage from lightning strikes. Can anybody describe what having an arrestor installed would entail? Is this something the power company has to perform, or can any qualified electrician do the work? How expensive is it? How effective is it, or do I have to supplement the arrestor with other safeguards?

Thanks!
128x128onhwy61

Showing 1 response by bob_bundus

Hi OnHwy61:
Surge protection is a wise investment & is certainly better than prayer alone. You may have read my old postings regarding my whole house surge protection by Joslyn Electronic Systems. This is a gas tube discharge primary arrestor (actually there are two large metal-envelope tubes, one for each 120V leg, mounted inside a metal box with fuses & neon pilot lights). I simply mounted the box on the basement wall next to my service panel. I shut off primary power on the pole outside & wired a #6 conductor in parallel with each incoming leg across the enterance lugs. The ground line coming back out of the Joslyn connects to service ground. The fuses are just for catastrophic meltdown protection, in case a tube shorts. These tubes fire at 140 volts, clamping transients to ground.
Actually the Joslyn is the 2nd-in-line protector. Utility company provides an MOV (metal oxide varistor) type arrestor on the 1500VAC incoming to the pole transformer. There is also a 3rd level of protection, this being a smaller 130V MOV paralled across the outlet for my dedicated AC line to the audio rig. The 4th protection level is another larger MOV contained within the Chang Lightspeed AC line conditioner; this is stock from the factory. In some cases (when warranty has expired) I even install another 130V MOV within components themselves.
All of this is still no guarantee of immunity. Once out of the two times that we were hit directly outside, I still experienced some damage, but it was at least survivable/repairable. Otherwise with no protection at all, the equipment would have been blown completely to smithereens. That's what happened the very first time, before I did all of the aforementioned. Other hits have occurred where the transients came in from further down the line. In these cases, when the Joslyn fires it hums loudly like a very large motor starting up. I experienced no damage at all from those incidents, nor from the power company switching transients that do occur from time to time as the Joslyn + MOV's handles them too.
True it is not always practical to unplug the equipment, but I still do that whenever possible. Since I always leave the rig powered on, there are times when no one is home to take care of things. There was even one incident where a $4000 amp was plugged in but not turned on; it was still damaged because a snubber capacitor was wired across the internal power switch & the cap coupled plenty of energy into the amp. The damage was minimal & repairable however; it would have been much worse & without any protection at all the amp would have been junk.