I will be looking at some work regarding a circuit that won't reset at the breaker in a home, and the fact that a lot of electronic equipment (t.v., stereo, computer monitors,) were ruined from lightning. Does anyone have any ideas what I could do to help them? Does it mean that the electrical service is not properly grounded or bonded? Or is it a freak accident, where the homeowners should be purchasing surge protectors for their electronic equip?
lightning strikes
- Thread starter leggo
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: lightning strikes
Surge supression, UL Listed to 14449 2 edition, is a good first start. You get what you pay for in TVSS. Put a wired module at the service panel and point of use units where electronic equipment is used. A low resistance grounding system may help some, but it really depends on how the service is installed-overhead or underground.
A most important consideration is to have all the communcations systems - phone-radio-tv-coax all grounded together right at the service, very close together. Minimize the lead length of the serive TVSS, better yet get a meter socket TVSS if your POCO will let you use one.
Surge supression, UL Listed to 14449 2 edition, is a good first start. You get what you pay for in TVSS. Put a wired module at the service panel and point of use units where electronic equipment is used. A low resistance grounding system may help some, but it really depends on how the service is installed-overhead or underground.
A most important consideration is to have all the communcations systems - phone-radio-tv-coax all grounded together right at the service, very close together. Minimize the lead length of the serive TVSS, better yet get a meter socket TVSS if your POCO will let you use one.
Re: lightning strikes
Some very good TVSS equipment that I have seen is made by Phoenix Contact.
http://eshop.phoenixcontact.com/phoenix/treeViewClick.do?UID=735098271
Don't mind the German at the top of the page. There is English lower down. This equipment is very inexpensive and easy to install.
Some very good TVSS equipment that I have seen is made by Phoenix Contact.
http://eshop.phoenixcontact.com/phoenix/treeViewClick.do?UID=735098271
Don't mind the German at the top of the page. There is English lower down. This equipment is very inexpensive and easy to install.
Re: lightning strikes
I will echo Tom's advice. First check your GEC, GES, and MBJ. Make sure those connections are tight and not corroded. Most use clamps at the rod, and I would bet you can pull it apart with your hands.
Second look very closely at the CATV , Telco, antenna, and any other line protectors. They should be connected to the service GEC very close to the meter base. Again most are clamps and are loose and corroded. A big problem is you will find no line protectors, or protectors will terminate to a isolated ground rod that is not bonded to the GES, of extremely long lead lengths back to the GEC due to the communication service entering some distance from the electrical service.
As for TVSS, the best units are a collar type plugged into the meter base. Some utilities supply then with guarantees for a small monthly fee. If not check with utility as Tom suggested to see if they will allow one to be installed. 2nd best alternative is to use TVSS built into the main panel. 3rd best is a parallel unit wired into the service panel. Extreme care must be used using a parallel unit concerning lead length. Any leads longer than 6 inches makes the unit worthless. As with any TVSS unit be sure you see the UL 1449 Seccond edition rating with a SVR of 400 volts or less for 240 volt systems and 330 for 120 recepts. Avoid units that only list Joule rating, it means absolutely nothing other than junk.
Last use a quality Class ?A? device or point of use TVSS at the devices. If it is a PC make sure to select one with Telco and/or coax protectors built in.
In regard to overhead or underground service, I assume Tom is referring to the likely hood of the service being hit. Overhead is more likely to being struck by lightning as opposed to underground.
[ June 18, 2004, 09:59 AM: Message edited by: dereckbc ]
I will echo Tom's advice. First check your GEC, GES, and MBJ. Make sure those connections are tight and not corroded. Most use clamps at the rod, and I would bet you can pull it apart with your hands.
Second look very closely at the CATV , Telco, antenna, and any other line protectors. They should be connected to the service GEC very close to the meter base. Again most are clamps and are loose and corroded. A big problem is you will find no line protectors, or protectors will terminate to a isolated ground rod that is not bonded to the GES, of extremely long lead lengths back to the GEC due to the communication service entering some distance from the electrical service.
As for TVSS, the best units are a collar type plugged into the meter base. Some utilities supply then with guarantees for a small monthly fee. If not check with utility as Tom suggested to see if they will allow one to be installed. 2nd best alternative is to use TVSS built into the main panel. 3rd best is a parallel unit wired into the service panel. Extreme care must be used using a parallel unit concerning lead length. Any leads longer than 6 inches makes the unit worthless. As with any TVSS unit be sure you see the UL 1449 Seccond edition rating with a SVR of 400 volts or less for 240 volt systems and 330 for 120 recepts. Avoid units that only list Joule rating, it means absolutely nothing other than junk.
Last use a quality Class ?A? device or point of use TVSS at the devices. If it is a PC make sure to select one with Telco and/or coax protectors built in.
In regard to overhead or underground service, I assume Tom is referring to the likely hood of the service being hit. Overhead is more likely to being struck by lightning as opposed to underground.
[ June 18, 2004, 09:59 AM: Message edited by: dereckbc ]
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: lightning strikes
cjcrawfo
I would only caution to make sure the phoenix TVSS is listed. What I saw early on was not listed, it may be now.
Ed, overhead could be more likely to take a direct hit. However even underground can have a surge from a neargy hit or if the lightning hits the primary.
Also, I have no proof of this, but if the meter is outside and the service disconnect inside, and the Grounding Electrode Conductor is connected inside the service, the lightning hits the lines, goes into the service and back out. It would seem to me to be safer if the grounding electrode conductor was bonded inside the meter can, but in some areas that is not allowed. Bonding inside the meter can would allow a direct path to ground.
cjcrawfo
I would only caution to make sure the phoenix TVSS is listed. What I saw early on was not listed, it may be now.
Ed, overhead could be more likely to take a direct hit. However even underground can have a surge from a neargy hit or if the lightning hits the primary.
Also, I have no proof of this, but if the meter is outside and the service disconnect inside, and the Grounding Electrode Conductor is connected inside the service, the lightning hits the lines, goes into the service and back out. It would seem to me to be safer if the grounding electrode conductor was bonded inside the meter can, but in some areas that is not allowed. Bonding inside the meter can would allow a direct path to ground.
Re: lightning strikes
Tom,
I check on the listing of that product with Phoenix in Harrisburg, PA and they email me the info all about the TVSS equipment and they also said it has been listed since the product was avaiable for our use. UL 1449 Second Edition.
Thanks for the concern!!!
Everyone have a safe day!
Chris Crawford
Tom,
I check on the listing of that product with Phoenix in Harrisburg, PA and they email me the info all about the TVSS equipment and they also said it has been listed since the product was avaiable for our use. UL 1449 Second Edition.
Thanks for the concern!!!
Everyone have a safe day!
Chris Crawford
- Status