Lightning Question And/Or Problem.

[jason]

Please help if you can. This is the situation. A customer of mine had me doing some basic electrical work in his home. While I was there he mentioned that lightning has been a major problem for him. He said that lightning has damaged everything he had a couple of different times. He had another electrical contractor come out and that electrician drove another ground rod or 2. He now has 3.

I was wrapping up what I was doing and when I went to put the breaker in, I noticed he had 3 wire to his panel. The panel was in the middle of the house. I knew it was more than 15' from the meter base. I went outside and he also had a disconnect. Meaning, of course, the wire to the inside panel shoulda been 4 wire.

Now, my questions are:

Being this installation is wrong, is this in any way causing him more problems with lightning? I know this isnt causing lightning to strike his place, but once it does, is this affecting his appliances in the home?

What are the dangers of NOT having 4 wires to the secondary panel?

I appreciate all responses.

 

[hurk27]

Re: Lightning Question And/Or Problem.

3 wires to the sub-panel while it is a code violation it is not the problem with lightning. The main thing to look for when haveing problems with lightning is a path that causes the lightning to come into the house to get to better grounding. (house neutral) In most cases I have seen it was the Telco and cable drops. There is alot of these drops that are made away from the service. and these installers will just install a short little rod and bond there drop to it with out any connection to the service grounding electrode that is required by the NEC. what happens is a lightning strike on the main trunk line will send the current down the drop to the house but instead of being drained off to the service electrod it traval on into the house through the appliance out to the neutral back to the panel to the service grounding electrode. and when it does it will take out the equipment in the proseces. This is not the path you want lightning to take. The idea is to provide a better path outside the house. to do this requires the bonding of all drop wires to the service electrodes with at least a #6

A good site to learn about lightning protection is: Lightning-Protection-Institute

Lightning Safety Institute

[ November 21, 2003, 12:43 AM: Message edited by: hurk27 ]

 

[earlydean]

Re: Lightning Question And/Or Problem.

If all else fails, install lightning arrestors on the service and telephone lines, outside, next to the metering location.