Earth ground electrode should connect short (ie 'less than 10 feet') to tha main breaker box. And that ground wire should not be in conduit. That ground wire has no relationship to the other wire that would go to the server room. If you choose to install everything in a server room, then it is easier to run one wire to a distribution box in that room. Then power various circuits from that distribution box.Originally Posted by hecktic
10 AWG would be for a 30 amp circuit. 8 AWG is simply the next thicker wire - a better conductor. Plugs define how much current (amps) that wire must provide. Code then tells the electrician how thick that wire must be. You need not worry about wire thickness; only about how much current (power) is needed.
The wire from main breaker box to the room will probably be in conduit. Code defines that for safety reasons. That conduit not to be confused with an earth ground wire that will be a bare, quarter inch, copper wire and not in conduit. That ground wire only connects to the main breaker box that also has the protector. The 30 amp circuit is one cable (conduit) from main breaker box to server room. The earth ground wire is a different single and bare wire that goes from main breaker box to earth. This bare wire is the one that must be short, no sharp bends, etc to the earth ground rod(s).
'Whole house' protectors are made by many well respected companies such as Siemsn, Square D, Cutler-Hammer, Intermatic, Leviton, and General Electric. These companies also make most other parts found in or that connect to breaker boxes. For example, Cutler-Hammer (Eaton) also makes breaker boxes and circuit breakers. A 'whole house' protector is just another part made by all these companies. Most important number for a 'whole house' protector is about 50,000 amps or higher. Most important number for the earth ground to that breaker box - connection to earth must be as short as 'practicable' (a word the code loves to use). And as you said, the protector is only in the mains breaker box so that surges can be connected as short as possible to earth.
And yes, more earth ground rods mean the 'whole house' protector is even better. Anything that makes the single point ground more conductive means the 'whole hosue' protector will divert even more surge energy harmless into earth. Faciltiies that require even more reliable protection literally surround the building with a buried bare copper wire. Even better protection - because protection is always about the quality of that earthing. New homes should have protection installed when the footing are poured - Ufer grounds. Mentioned for others who are following. But that solution is not relevant to your venue.
Meter defines where the main breaker box (different from distribution breaker boxes) and earth ground are located. For example, inspecting earth ground connections and installing ae surge protector requires access to that meter room. If you normally do not have access to that room, then another reason to have a server room distribution box so that breakers are quickly and easily accessed. You do not want communication equipment unpowered (breaker tripped) because someone cannot find a key to that meter room.
It sounds like he is talking about installing a better earth ground (more rods) closer to the main box. Better earthing means the 'whole house' protector works better. Every 'layer' of protection is defined by the only item required in every layer - the earth ground. So, your primary surge protection is installed by the utility at the pole (or in a ground level transformer box). Visual inspection of the primary protection layer is this picture:
http://www.tvtower.com/fpl.html
All utility wires (power, telephone, cable TV) should connect to this earth ground.
Secondary protection layer is defined by the earth ground at the main breaker box and meter. Every incoming wire in every cable connects to this earth ground either directly (cable TV) or via a protector (AC electric, telephone).
And then some facilities do a third layer. IOW the server room then has earthing in the floor. And all wires enter the room at the same side. All wires again connect to this earth ground directly or via a protector. That is why some facilities also use the raised computer floor. That grounded floor is part of the third protection layer separated from everything else in the building only earthed by the secondary protection layer. Sort of a building isolated and separatedly earthed inside a building.
If you implement a third protection layer, even phone wires must enter and be earthed (via a protector) just all other wires and ducts. All depends upon how 'hardened' you want to make your facility. But then facilities that are that extensive also have electric generators for backup power.
Implementing the third protection layer with a sever room earth ground and without doing it religiously is a good idea - because it is additional protection done on the cheap.
So, let's assume KVM. If outside the room, then CRT, mouse, and keyboard cables would have to connect to that single point ground where wires leave the room. Or the KVM area must be integrated as part of the server room's "third protection layer". IOW the KVM might be done with some converter so that mouse, keyboard, and CRT wires interconnect via some other hardware standard that is 'easy to implement' protection / earthing. And since mouse, keyboard, etc cables have distance restrictions, that converter would also be necessary to connect KVM outside the server room. (Black Box is one company that provides unique and strange solutions for such distant KVM implementations.)
Radiologists transformer would not cause problems. In fact, many commericial 'buildings have transformers inside the building - not on the utility pole, etc. These will convert 4,000 or 33,000 volts (wires that enter the building at voltages that high) to 120/240 volts. (Which is why some meter rooms are restricted access.) Being nearby or inside the buiding does not cause any additional problems. Your air conditioner is more likely to cause 'surges'.
Further confirm that 'no problem'. Operate an old style CRT monitor adjacent to that wall closest to the radiologist's transformer. If his transfomer is generating 'fields', that CRT picture will be distorted by those fields. And those fields still will (should) not be destructive to other equipment.
That CRT test may even discover high current, low voltage (120/240v) wires inside the walls. Sometimes wires to a stove under the floor can distort a CRT when the stove operates. Many worry about high voltages when electromagnetic field interference is more often due to lower voltage, high current wires.
Only problem created by the radiologist's transformer might be minor voltage variations - also called noise - that should be made irrelevant by power supplies inside all electronics. When the X-ray machine runs, you might hear that noise on an AM radio as it power cycles. And then you might learn how many other devices create far more electrical noise. (Tuning an AM radio to distant stations makes it a better 'noise' detector.)
The Kil-a-Watt is another good tool. Notice that V-A number will be different from watts. Watts is power used by equipment. V-A is the actual power consumed. V-A will be same for an incandescant bulb and will be higher for electronics. Bulb has a power factor of 1. Electronics create a power factor problem. Electronics might have a power factor of 0.7. In simple terms, electronics only use .7 amps productively for every one amp consumed. Some larger facilties install power factor correction so that more energy they pay for gets used productively.
Power cosumed by appliances (per Kil-A-Wat) will be less than the number on its power label. What appliances consume typically averages less than the maximum number on that label. A UPS is sized for the maximum number. UPS must be able to provide those peak demands.
30 amps is significant power. Rare is a server closet consuming that much power (something less than 3600 watts). I doubt your equipment will consume that much power - generate that much heat.
Running a 60 amp wire (ie same wire to a buiding wide air conditioner) means even less voltage variation in the room as the load changes. Costs very little more. Makes any future upgrades simple (Just like homes upgraded from 60 amp service to 200 amp service - cheaper was to do it right the first time).
One mistake made by those who have a server 'closet' is that the amount of air moved through that closet is defined by wattage (power dissipated). Just having ventilation is not sufficient. How many CFMs (cubic feet per minute) defines whether the room has sufficient air flow to remove the heat. Small rooms (closets) often do not have sufficient air flow. In simple terms, air flow is defined by the vent duct 'cross sectonal' area. More square inches means more air moved.
Camera typically is not be useful for hardware security. Hardware failures rarely have any visual indication. Sensitive smoke detector (fire alarm) in that room should be more than sufficient for anything that the camera might see - except humans. Camera is important for human security. If really into security, so that someone unconcious in the computer room does not lay there undiscovered over the weekend. Or so that theives can be identified.
BTW, you did not discuss secure data lines - so that vandals do not break communication or implement data theft devices. Netscape had a interesting security device for their data cables. Those cables were in a cast iron pipe often found in older homes for bathroom and kitchen sewage. To compromise the data cables, one had to crack that cast iron. Compromised data easily discovered since the pipe was easily observed by anyone.
Smoke sensitive detectors would do most to protect that hardware room. Of course, no smoking permitted. If the room is properly wired and ventilated, then the amount of power in that room is irrelevant.
KVM and other such solutions are interesting. Humans working in a room more condusive to productive work. More important than cameras is software that can monitor the health of all computer equipment and sound an alarm. So that the KVM remote station can 'see' the failure. Electric power is so reliable that an electrician on call is unnecessary. Far more likely are software failures or a failed server storage device or communication failure. Useful is a separte 'systems health monitor' work area implemented in a nearby quiet workspace.
Important point of that IEEE paper are pictures of how various equpment should be interconnected. In your case, that means extreme electromagnectic fields are less likely to cause data loss, slower data transfers, or interruption. Paper applies mostly to how data cabling is routed. The point is in something like four (somewhat cryptic) points made in the conclusions. An electrician typically would not understand any of that. Electricians spend significant time learning code - that is mostly about human safety and the avoidance of fire. Electricians typically would not understand the reasons in that paper - only understand what must be done. 'Second half' pictures demonstrate what to do.
If rewring a new room, then you might have high reliabiiity circuits - to servers and communcation equipment. And less reliable circuts - to printers. And maybe even switched circuits so that a wall switch powers off everything not required during unmanned operation. For example, if one server can supplement another, then having both servers on separate circuit breakes is a smarter option.
One operation has one power switch(es) adjacent to the door. This powers off all desks and associated electronics at the end of the day. Only machines left powered are the fax and other 24 hour equipment. An easy way to power off everything unnecessary and to reduce the risk of fire (ie somebody left on a small heater). Something to think about if doing that much rewiring. Areas that have much human interaction also have a higher fire risk due to something inadvertantly left powered on over the weekend.
I hope I have covered everything. So this was a simple question about a UPS.
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