And I'm not sure what you're on if you think UPS power is dirtier than the mains.
A UPS that outputs square waves will also measure a stable voltage. Is that 'clean'? Of course not. Others demonstrate what a typical UPS outputs. View pictures:
http://img260.imageshack.us/img260/8540/apcbu650load.jpg
A utility also demonstrates clean power from AC mains (on left) and what happens when that UPS switches to battery:
http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-03.asp
Why is UPS power so dirty? First, because dirty UPS power is sufficient for all electronics. Second, a UPS is typically made as cheap as possible. And third, efficiencies increase when not adding additional power absorbing compnents to make a 'cleaner' sine wave.
Of course, if one knows a UPS is cleaner power, then a manufacturer spec number defines 'clean' (ie %THD). First indication of recommendations based in hearsay is an empty and subjective denial - no numbers. Instead, denials are based in feelings. No facts. No numbers.
Armageus does post numbers. An APC claims 368 joules. So it absorbs maybe 123 joules and never more than 245 joules. A destructive surge means it must somehow absorb hundreds of thousands of joules.
Due to protection already inside electronics, a 250 joule surge is converted by its power supply into rock solid, stable, DC voltages. It converts a tiny surge to power its seminconductors. 245 joules protection in that APC is near zero protection. And only from a type of surge that typically does not cause damage. Concern is for a completely different type of surge that actually does damage.
What happens when a surge is a paltry 1000 joules? That tiny surge will damage an undersized protector. A fuse must disconnect its tiny protectors parts as fast as possible to avert a fire. Fire is another problem with grossly undersized protector circuits. Meanwhile that surge remains connected to an appliance that harmlessly absorbs that energy. That converts that surge to power its semiconductors. Better protection is standard inside electronics.
Other numbers also say nothing about protection. For example, UL is about human safety; not about transistor safety. To meet UL1449, a protector circuit must disconnect as fast as possible to not create a fire. To protect human life. UL1449 says nothing about protecting transistors. UL is completely about protecting human life. UL standards are created by the
National Fire Protection Association.
My UPS is also marketed as a pure sine wave UPS. It outputs square waves as demonstrated in those pictures. Those square waves and spikes are nothing more than a sum of pure sine waves. As taught in high school math. They did not lie. They said it outputs pure sine waves. Then hope naive consumers use speculation justified by emotions to assume it is cleaner power.
A square wave output is dirty and ideal power for all electronics. But may be harmful to motorized appliances. It will measure right on voltage. Is still 'dirty' power. And perfectly good for electronics that also means tiny surges are only noise.
Everyone's concern is a rare surge, maybe once every seven years (less often in the UK), that can overwhelm existing protection. Nothing on a power cord claims to protect from that type of surge. Nothing - as demonstrated by specifications provided by Armageus.
I maintain that it is a product that isn't necessary in the UK.
So many if not most who make these recommendations do not even know how protection was accomplished even 100 years ago. These solutions also cost maybe tens of times less money. These products were cited multiple times.
However useful and effective soutions from Kieson, ABB, and Siemens do exist.
These products or similar ones are always found in every facility that cannot have damage. Local (adjacent) protectors are not. In fact, British Telephone wants their protectors up to 50 meters distant from electronics. That separation INCREASES protection.
Eaton (also called Cutler-Hammer) is but one of so many, with superior integrity. Lightning is one example of a surge. Typically 20,000 amps. So one 'whole house' protector (from more responsible companies) implements features not found in or discussed by a UPS, power strip, or rack mounted protector.
First and foremost is a low impedance (ie 'less than 3 meter') connection to single point earth ground. Second, is a spec number that says it will dissipate even direct lightning strikes (ie hundreds of thousands of joules) harmlessly without damaging a protector. A minimal 'whole house' protector is 50,000 amps.
One 'whole house' solution (essential to even protect a furnace, all RCDs, clocks, and an APC UPS) is protection from all types of surges. Typically costs about £1 per protected appliance. Should remain functional for decades. And must have what is essential for every protection system.
Best protection for anything is a hardwire from each wire in every incoming utility cable to earth. However telephone and AC electric would not work. So we do a next best thing. Connect a 'whole house' protector to do what a hardwire would do better.
A proven 'whole house' solution does not claim to absorb a near zero 368 joules. An effective solution, implemented in every nation throughout the world, connects 20,000 amp surges to what harmlessly absorbs hundreds of thousands of joules. All four words have major electrical significance: single point earth ground. We have not yet discussed THE most critical component in every effective protection system - the 'art' of protection. Because some are having so much trouble just learning its simple science.
Concepts are based in what Franklin demonstrated in 1752. Effective protection of appliances was first introduced in primary school science.
Kudos to Armageus for trying to provide numbers. Doing so is how to learn from our mistakes. All electronics already contain protection equal or superior to anything that might be attached to its power cord (ie rack mounted box). Concern is a rare surge, typically once every seven years, that may overwhelm that protection. That rare surge is why everyone who cannot have damage (ie nuclear hardened military facilities, rocket launch pads, Orange, BT, munitions dumps, BBC, etc) always implement this 'whole house' solution. Always. So that hundreds of thousands of joules harmlessly dissipate outside. So that nobody even knew a surge existed.
A soundbyte summarizes what is most important. A protector is only as effective as its earth ground. Protection is always about where hundreds of thousands of joules harmlessly dissipate. As understood over 100 years ago.
