Steel Roof Grounding

[CobyRupert]

What size wire can carry 5000 Amps to 200,000 Amps? Super conductor wire?

How long does it need to carry those currents?

It's not the current that destroys thing, it's the heat, which is a function of time.

Bond the roof to the lightning rod down conductors.

See NFPA 780.

 

[Zerk]

It is true conductors need to be bigger for longer loads. I am not sure if lightning protection concerned about heat though. It is giving it a path to ground. I would think it would be quick. Big faults last a short time, and can melt things. I have seen 40 second faults melt copper bus bar. But 40 seconds is an eternity. Not like motors, transformers or condcutors, which carry loads as part of their service. Faults are quick.

Electric world faults are a few cycles. A cycle is 1/60 of a second.

 

[CalG]

How long does it need to carry those currents?

It's not the current that destroys thing, it's the heat, which is a function of time.

Bond the roof to the lightning rod down conductors.



See NFPA 780.

The problem in dealing with "the cure", is that the patient is still dying.
When working on prevention, there is no patient.

Dissipate the potential, and there will be no strike!

 

[Industrial Toys]

Thanks

I will just reinstall the protection as it was hoping that ths will somewhat ground the roof.

It was actually pathetic, the small rods that were used to ground the original system. Maybe my Dad had a thing or two to do with that. Hire an expert and then give them junk you have on hand to save money.

I had excavated down to the foundation a couple of years ago, and was snooping around a friends place for a ground rod (to save money) and ended up getting a galvanized headache rack of of a truck, that was scrap. I just threw that in the hole for a ground. It should last a very long time and has a good amount of surface contact. Pitty the poor guy that digs it up some day!

 

[teejk]

For a funny read on lightening rods check out Mark Twain's "Political Economy". Short read..."Single point grounding" would see to dictate a lot of wire to all come back to the point where your main electrical service grounds to. I built this house in 2010 and code required me to install a grounding block connected to the main grounding rods so cable, telephone, etc. could all come back to that. In the meantime I have Dish satellite and Hughes satellite...the installers had never heard about that and sunk their own ground rods. My shop is all metal and about 100' from the house. The electrical panel feeds from the house and I didn't use that little green screw to "bond" the panel (which I guess let's the neutral and ground wires to travel their own path back to the main panel where they are indeed "bonded"). I don't quite understand the need but I don't understand much of current NEC requirements that we never had to worry about just a few years ago (like GFCI outlets, tamper resistant outlets and now "arc fault" outlets...I guess one or two people a year did something stupid so everybody has to pay more).

 

[Zerk]

For a funny read on lightening rods check out Mark Twain's "Political Economy". Short read..."Single point grounding" would see to dictate a lot of wire to all come back to the point where your main electrical service grounds to. I built this house in 2010 and code required me to install a grounding block connected to the main grounding rods so cable, telephone, etc. could all come back to that. In the meantime I have Dish satellite and Hughes satellite...the installers had never heard about that and sunk their own ground rods. My shop is all metal and about 100' from the house. The electrical panel feeds from the house and I didn't use that little green screw to "bond" the panel (which I guess let's the neutral and ground wires to travel their own path back to the main panel where they are indeed "bonded"). I don't quite understand the need but I don't understand much of current NEC requirements that we never had to worry about just a few years ago (like GFCI outlets, tamper resistant outlets and now "arc fault" outlets...I guess one or two people a year did something stupid so everybody has to pay more).

GFIs are nothing new and not a bad thing. Though they can be a nuicance because they do fail. One could argue we were taught not to mix electricity and water.


A sub panel ground and neutral should not be connected at that subpanel, but at the main panel. The sub panel should be grounded. But the green screw should not go through where the neutrals are landed into the panel, which is grounded. Neutrals and grounds should be kept seperate on a sub panel. That is nothing new. Was that way when I started 20 years ago, probably alot longer.

Also are you sure you should have been installing your own electric?

 

[teejk]

GFIs are nothing new and not a bad thing. Though they can be a nuicance because they do fail. One could argue we were taught not to mix electricity and water.


A sub panel ground and neutral should not be connected at that subpanel, but at the main panel. The sub panel should be grounded. But the green screw should not go through where the neutrals are landed into the panel, which is grounded. Neutrals and grounds should be kept seperate on a sub panel. That is nothing new. Was that way when I started 20 years ago, probably alot longer.

Also are you sure you should have been installing your own electric?

Yeah I'm sure I can handle most electrical things (our inspector was quite impressed). And I know about the little green screw...funny thing there is the professional that helped on this house says he uses them all the time! But thanks for your comment.

 

[dickfoster]

Thanks

I will just reinstall the protection as it was hoping that ths will somewhat ground the roof.

It was actually pathetic, the small rods that were used to ground the original system. Maybe my Dad had a thing or two to do with that. Hire an expert and then give them junk you have on hand to save money.

I had excavated down to the foundation a couple of years ago, and was snooping around a friends place for a ground rod (to save money) and ended up getting a galvanized headache rack of of a truck, that was scrap. I just threw that in the hole for a ground. It should last a very long time and has a good amount of surface contact. Pitty the poor guy that digs it up some day!

Well if the steel roof is bonded well it can form Faraday Cage of sorts and block the black helicopters from listening in so easily. Then you can take you tin foil hat off while under the steel roof.

 

[Zerk]

Problem is grounding all the sheets.

But they do create a problem for cell signals.

 

[Redneck in training]

Our house has metal roof and siding. When it was new we had either direct or near lightning hit. Every electronic light switch (1200 USD worth of them) burned. I called the manufacturer (Lutron) and they replaced all of them without a single question asked. After that I installed whole house surge protection. Had to replace it once because it was destroyed by a power surge caused by the utility. We get direct or close hit at least once a year but so far had no damage.
We have a weather station about 300 ft away from the house with wind sensor on a 33 ft tall pylon that has a lightning rod grounded by about 5 or 6 AWG wire on the top. I saw it being hit by lightning and didn't observe any damage to the wire. My guess is the the energy travels around the wire in ionized air.