Westom certainly earns points for consistency...
Funny how none of his sources reference a 10' (or less) connection to earth ground even though that's a central tenant of his claims. He also doesn't seem to understand that the electrical neutral and ground are both connected to earth ground at the electrical panel.
The shorter the length of the grounding conductor, the lower the induced voltage that will occur as a result of a direct strike. However, as you correctly point out, w-dude has no conceptual understanding of house wiring, electronics, magnetics, nor even surge supression technology. He consistently cuts and pastes the work of others without an understanding. That is dangerous should others believe what he pastes.
In general, the little blurbs copies may not be incorrect, but the context in which the blurbs are use is horribly mis-understood and can be dangerous.
Well, I'd hate to see this turn into a bash him or her thread because I just finished reading through one on a very closely related topic....
It is unfortunate indeed when cut and paste content is used to pretend expertise. Lack of knowledge leads to advice which can be troublesome in the least, lethal in the worst.
So, knowing a lightning strike is going do damage and I cannot do anything about that given the circumstances, what joule rating covers the majority of damaging spikes? True that UPSes do not have high ratings. The power conditioner has the highest I've owned (5000+). Just looking for base line protection from things that happen every day.
The problem should be approached with a multi-tiered solution.
1. Reduce the possibility of a reference problem. This is what Martzloff writes about. All buildings must have a single point of entry for all conductive cabling which service the building. Nearby strikes can generate voltages between lines entering a building if they are not tied together to a common earth at the same location.
2. Reduce the line to line, line to neutral, line to ground, and and neutral to ground transients. This is typically done within the house by a whole house device located at the service panel.
3. Use a two port surge supressor at the equipment. This reduces further any transient or surge voltage at the end of branch, and it stops reference float as a result of the EM pulse generated by a nearby strike.
edit: if there is only one end device with only the power cord, the cheap throwaway spd's will give some protection, but they are not very robust given the price point.
Keep in mind a good surge protector diverts the surge to the ground, rather than only trying to use the MOV to absorb it.
Actually, a surge protector does not do that. This misconception also leads to the erroneous statement that a "surge protector is only as good as the earth ground"..that is terribly wrong, and any engineer understands why.
What they will do however, is clamp the potential between line, neutral, and ground. It does not "divert" the surge. A surge protector is incapable of holding the house reference voltage anywhere. The reference will float to whatever results from the earthing conductor impedance in series with the earthing rod(s) resistance to earth (which by code is less than 25 ohms).
The higher the joule rating the more energy can be absorbed by the unit before the MOV burns out. So a lower rated unit may just stop protecting after fewer surges (which is why you want one with an indicator for when it fails).
Correct, full agreement.
For better applications, the use of a whole house spd at the panel working in cascade coordination with a two port end of branch one will provide most a higher level of protection. The whole house units generally have a higher let through voltage, typically 400 volts, while the end of branch will be a little lower, either 300 or 350. During a transient, that difference combined with a run of romex with series resistance, will help the end of branch device survive a transient that would normally cause it to fold it's tent..
Line surges which are sufficiently high or of enough duration, cannot be stopped by a clamp device typical of consumer units.. The source impedance from the utility company guarantees a containment breach for any mov hapless enough to be there. For this scenario, automatic disconnection by a smart ups is the best solution.
Cheers, John
