Re: UPS/Power conditioning questions

From: DL Phillips (whohe_at_whoever.com)
Date: 03/12/05 

Date: 11 Mar 2005 15:02:32 -0800

w_tom wrote:
> Take a $3 power strip. Add some $0.10 components. Sell it
> for a massive price increase of $15 or $50. Then make a half
> truth claim about surge protection. That same circuit is also
> the protection inside the plug-in UPS. Protection only from
> one type of transient. As demonstrated here, others will then
> assume it is protection from *all* types of transients.
> Assumption made because quoted manufacturer uses half-truths.
>
> Plug-in UPS does not provide effective protection. Citing
> quote has no credibility. It provides no numbers and no
> science facts. Of the five power problems - blackout,
> brownout, harmonics, noise, and transients - which one does it
> claim to protect from? Missing are important facts. Those
> missing facts would expose ineffective protection.
>

Four additional types of power problems are Power Failure, Overvoltage,
Sags and Frequency Variation. To address all nine types of power
problems, there are three types of power protection: Surge Suppression,
Power Conditioning and Battery Backup.

You should pick the level of protection needed based on the condition
of the power at the outlet you need to use. If the power is conditioned
and surge protected at the service entrance and the outlet is on an
isolated circuit, then a more simple UPS will suffice. If you're on an
upper floor of a large office building that you don't own, and you have
no control over the power, then your needs are greater.

> How does one identify an ineffective protector - power strip
> or UPS? 1) No dedicated connection to earth ground and 2)
> manufacturer avoids all mention of earthing. What does that
> APC forget to discuss? No earth ground means no effective
> protection - which applies to all plug-in UPSes.
>
> Real world protector companies discuss earth ground ...
> extensively. Why? A surge protector is not surge
> protection. Surge protector and surge protection are two
> different components of a surge protection 'system'. An
> effective 'system' always requires surge protection. But the
> 'system' does not always need a surge protector. What does
> the surge protector (ie inside a UPS) do? Connects a
> transient to surge protection. But (just like in that plug-in
> UPS recommendation), if the surge protectors does not connect
> to surge protection, then no effective protection.
>
> Surge protection is the single point earth ground.
> Effective surge protectors (that cost about $1 per protected
> appliance) are called 'whole house' protectors. They make
> (and notice the important numbers) a less than 10 foot
> connection to surge protection - earth ground. Some effective
> protectors are sold in Home Depot (Intermatic IG1240RC) and in

That unit costs around $90 and where I live it must be installed by a
licensed electrician. Then, there's a cost per protected appliance on
top of that. Saying $1 is a bit misleading.

> Lowes (Cutler Hammer and GE). But again, that APC product?
> Well good luck finding an APC product that are part of an
> effective protection 'system'. Some APC products do provide
> that earthing connection. Most do not. And that recommended
> UPS for transient protection? Only from transients that
> typically do not exist. IOW ineffective protection was
> erroneously recommended by others - as demonstrated by
> electrical principles well proven more than 60 years ago.
>
> BTW, you seem to feel that a computer connected to AC mains
> via a UPS is somehow isolated from those mains.

Some are, some aren't. Level 3 UPSes usually do provide isolation.
Level 1 and 2, probably not. But, you can't make blanket statements
about the features or quality of UPSes any more than you can about
Computers or Dishwashers or Automobiles. You've got to read the spec
sheets.

>Again, a so
> common myth. When the typical plug-in UPS is in battery
> backup mode, then computer is connected directly to AC mains?

There is no such thing as a *typical* plug in UPS.

> Where is the protection? Is that relay inside the UPS going
> to protect computer hardware? Of course not. They just
> forgot to mention that part.
>

Different units work differently and what you are saying might be true
for one unit but not for another.

> The OP asked for power protection; not a solution to power
> interruption. The UPS recommendation is only for power
> interruption AND violates those two symptoms of ineffective
> protectors. Listed were five types of power problems.

Nine types of problems. Where I live we get all nine most every
springtime and they can happen within seconds of each other. Even a
cheap UPS is better than nothing. No, it doesn't afford the level of
protection you're talking about, but the UPS's battery backup is just
as important as surge protection and power conditioning for power
protection.

> For
> effective hardware protection, a less expensive solution (at
> about $1 per protected appliance) is also the vastly superior
> solution. Posted previously are solutions even sold in Home
> Depot and Lowes. The UPS recommendation is bogus - to be
> polite because it is promoted by technical distortion and half
> truths. APC - like Monster Cable - is not a serious
> manufacturer of transient protection. Why do you think they
> never mention earthing? They fear you might learn : no earth
> ground means no effective protection.
>

I can't begin to count how many intermittent problems I've solved with
computers, time-clocks, printers and such out in some shop or office by
plugging it into a cheap UPS. I agree mostly with what you've said, but
we can only control those things over which we have control.

 -Doug