We are in the process of engineering the wiring for the a building and need to know if we should put special surge or lightning protection on the circuits that will be running the computers or the standard protection for the building is adequate.
Approximately 5-8 computers will be running at this location 24/7
it will be in northeastern kansas... lightning can be an issue, especially during tornado season. The main thing i think is, (this was handed down to me to research) we want to eliminate using multiple standalone surge protectors for these PC's and can we just beef up the wiring systems to withstand anything we could forsee
Here in interior Alaska when we wire the computer buildings for the US Army Stryker Brigade that uses one hell of lot of computers a UL certified lightning protection system is installed. We have one contractor, Star Electric in Fairbanks, Alaska that has the certification.
Surge protectors and surge protection are two completely different components of a building's protection 'system'. Protectors are nothing more than a temporary connection to protection. They are shunt mode devices. Every incoming wire in every cable incoming to a building (because every wire inside a building must be part of the 'system') must be earthed where entering. All wires must make a 'less than 10 foot' connection to same earthing electrode.
Principles are defined in this application note and figure from one industry professional:
Effective surge protector is nothing more than a temporary connection to earthing. That protector will only be as effective as its earth ground AND its connection to that earthing. Even that connecting wire must exceed what is required by post 1990 NEC. For example, no splices, no sharp bends, not inside metallic conduit, and as short as practicable to earthing electrode. That means the wire does not go up over foundation and down to an earthing rod. Instead that wire goes through foundation and down to earthing rod so that ground wire is feet shorter.
Earthing wires must also remain separated from other none earthing wires. Earthing wires for each utility must remain separate until all meet at the same earthing electrode.
Further discussion in previous posts: How transmission lines would not damage the telephone exchange (CO) or modems in the newsgroup tmnet.communities on 1 Dec 2006 entitled Question at:
Because an exchange cannot be damaged by
Same concepts to eliminate lightning damage to inverters for photovoltaic system in the newsgroup alt.solar.photovoltaic on 29 Nov
2006 entitled Problems during Lightning Storms at and in following posts:
Appreciate that well over 90% of all trees struck
How telephone appliances may have been damaged and how that damage could have been averted in the newsgroup rec.games.computer.ultima.dragons on 29 Nov 2006 entitled Thunder and lightning at:
Reasons for surge protectors are protection from
im.your.c> We are in the process of engineering the wiring for the a building and
The best information I have seen on surges and surge protection is at
the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits" published by the IEEE in 2005 (the IEEE is the dominant organization of electrical and electronic engineers in the US).
A second guide is
this is the "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home" published by the National Institute of Standards and Technology (the US government agency formerly called the National Bureau of Standards) in 2001
The IEEE guide is better (the NIST guide is less technical).
A service panel surge protector should be used. The guides give informition on sizing.
Also note the information on single point grounding. The phone and other incoming non-power wiring should have their protectors near the power wiring entry and those protectors should connect to the grounding electrode conductor from the power service close to the power service. Any significant earthing currents from a surge will cause the "ground" in the building to rise above 'absolute' earth potential. You want the grounds for the power system (ground/neutral bond connection) to rise together with the phone and other incoming systems so there is not a damaging potential difference between them.
How much additional protection depends on how critical the computers are. They could, for instance, run from a subpanel with its own surge protector and have adjacent surge protectors for signal wires to the computers connected with short wires to the subpanel ground - a local single point ground.
More information is in the "IEEE Recommended Practice for Powering and Grounding Electronic Equipment", the IEEE "Emerald" book. If interested you can get an abstract, the table contents, and chapter 1 - overview at:
When we wire FAA jobs that use a lot of electronics we always install a surge or lightning protector at the service to their buildings. Also, lightning protection is installed at the building. In Kansas I would install both the lightning protection at the service and at the building. I see a lot of posts on technicl material here, but these types of protection systems are a matter of fact and have been engineered many times by existing users. Just call your local FAA shop electricians - these guys are experts on installing these systems.
Since you don't mention UPS systems, I guess you are planning on having frequent downtime. Hint: the better grade UPS systems already have better surge suppression built into them. It all depends on your building ground system. Read the references that were mentioned in the other replies.
I'd not do anything special to the building power system, other then making sure the ground system is better than the minimums established by the electrical code. Remember that the electrical code establishes the minimum safe standards, not best practices. The UPS for each system will do much better at protecting against more than just surges.