Lightning strikes!

[Salamander]

We had a very loud lightning strike last Friday night. Woke up to discover a couple of cable boxes not working, our TV had one HDMI connection fried, the modem was out of order, and a DVD player was also toast. All the toasted items were connected to surge protectors.

Right next to the modem sits a UPS to which my desktop and router were plugged in. As near as I can tell, they are both fine.

Thank goodness for the UPS. Should I plug the modem into it as well, even though it has a backup battery inside? I've read where that is a bad idea.

 

[mfenn]

Yes, go ahead and plug the modem into it. You'll potentially lose some efficiency due to the battery charger on the modem taking a square wave or modified square wave input instead of a true sine, but it's not worth potentially losing the $100 modem.

 

[Blain]

We had a very loud lightning strike last Friday night. Woke up to discover a couple of cable boxes not working, our TV had one HDMI connection fried, the modem was out of order, and a DVD player was also toast. All the toasted items were connected to surge protectors.

Right next to the modem sits a UPS to which my desktop and router were plugged in. As near as I can tell, they are both fine.

Thank goodness for the UPS. Should I plug the modem into it as well, even though it has a backup battery inside? I've read where that is a bad idea.

After a close lightning strike, I would view all protection systems as compromised (even if they "seem fine"), and replace them as soon as possible.

 

[piasabird]

It is hard to totally be protected from lightning strikes. They can come in through network lines too. Plus if possible, it helps to have a grounding line protector too where the power comes into the house. However lightning can hit the house anywhere. If it actually hits your house who knows what will happen. I had a friend whose refrigerator went bad from an electrical storm. I don't know if it was the lightning or a surge from the power coming back on.

Older houses have copper lines and iron pipes that go into the ground. These new houses are all plastic pipes. You cant ground a plastic pipe.

 

[westom]

Thank goodness for the UPS. Should I plug the modem into it as well, even though it has a backup battery inside? I've read where that is a bad idea.

You have no reason to believe a UPS did protection. First, because the manufacturer does not claim to protect from such surges. Second, because devices that actually protected the UPS, desktop, router, furnace, dishwasher, clocks, and washing machine were cable boxes, TV, and modem.

A surge was incoming to everything. Damaged were appliances that connected that surge to earth. Surge has no reason to be both incoming and outgoing via a UPS, desktop and router. Since it found better connections to earth destructively via other appliances.

You had damage because a surge was not harmlessly absorbed outside. Once that surge is all but invited inside, then that current hunts for and damages best connections to earth. Apparently you did not earth a 'whole house' protector - all but inviting that surge to go hunting destructively.

 

[BarkingGhostar]

Three years ago my neighbor across the street got hit by lightning for a second time. In this event, about a dozen houses on the street, including mine, suffered damage. The only problem was that every piece of electronics was plugged into a surge and uninterruptable device.

I reviewing what got damaged in the other homes, the electric company stated it was their belief that this strike was strong enough to saturate the granite underneath our neighborhood and cause a surge up the household grounds.

Guess what isn't protected by this kind of electrical surge intrusion? We had cable, DBS, telephone, electric and other companies out here for a week doing repairs. Now the strange part of the incident:

The electronics lacking a ground prong were safe, and those with grounded cords meeting at HDMI interfaces were killed. 60GB PS3 with grounded cord died with TV's HDMI interface. PS3 Slim without grounded cord was safe, as was the HDMI interface it was plugged into.

Same went for a lot of other equipment. Lucky for me, a lot of the more expensive equipment was deliberately unplugged due to a storm the night before, and my home theater got lucky.

 

[westom]

I reviewing what got damaged in the other homes, the electric company stated it was their belief that this strike was strong enough to saturate the granite underneath our neighborhood and cause a surge up the household grounds.

If a single point earth ground was implemented, then everything inside the house might be raised to 10,000 volts. IOW no significant voltage difference anywhere inside. No damage.

He installed a facility where neighbors were suffering similar damage. He implemented an Ufer ground as the single point earth ground:
http://scott-inc.com/html/ufer.htm

Damage is averted by a properly installed earth ground. Single point earth ground. Routine is protection even from direct lightning strikes. If damage happens, an investigation starts with earthing defects. Earthing is the art of protection. A destructive voltage inside can only exist when the earthing is defective. Often traceable to a human mistake.

 

[Blain]

People shouldn't forget that surge protectors and to some degree UPS units are "sacrificial" components.
One of their main duties is to give their lives to save your valuable electronics connected to them.
Unless they are high quality non-MOV designs, they should be replaced after a major event.

 

[bononos]

This is a good thread about surge suppressors. Quick summary- they are a good idea.
Are surge surpressors still necessary today?

 

[Matt1970]

Surge protectors are a good idea but lightning can damage components that aren't even plugged in due to the electromagnetic field they produce.