Lightning protection AND putting a receptacle on UPS

Page 3 of 5  


According to the specs at
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
it has less than 5% total harmonic distortion.

I am not sure why that is so. A WHSP protects two hots, and UPS only one hot.

I am not really

I can easily trace its output with an oscilloscope tonight and make some photos. That's a good question.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
5% THD should be sufficient for most electrical loads. That suggests this UPS was a more expensive type - is more than computer grade.
To define hot spots and protection, first define where the earthing spot is. Your primary protection is demonstrated in these pictures: http://www.tvtower.com/fpl.html
Also inspect your primary protection system - which you cannot repair.
That is your first layer of protection. Your 'whole house' protector and earthing system is a second layer. Protection inside electronics may be thought of as the third layer.
To be effective, point of use protectors must earth all the way back to the same earth ground provided to a 'whole house' protector. IOW point of use don't do much - no effective grounding. Even worse, point of use protector can induce transients onto other wires in that same wire bundle. The ground wire being too long and not separated from other wires.
In higher reliability facilities, whole rooms may become a building inside a building. Every wire entering the room is connected to a big ground that surrounds the room. Then a point of use protector is grounded to a third layer - a third single point earth ground system - that is that room. In this case, a point of use protector now has a function. A function, BTW, that can be compromised if any wire leaves the room without a connection (direct of via protector) first to that common entrance protection ground.
Layers of protection are defined by the single point ground. We keep it simpler in dwellings. Primary protector provided by the utility. Secondary protection is the household earthing system - with peripheral components such as 'whole house' protector (ie AC electric and telephone) or direct wire connection from each incoming utility wire (ie cable TV).
Where single point grounding is established determines where the protection layer is located. Protectors don't define protection location. Where those protectors are grounded - that defined where the protection exists.
Ignoramus32515 wrote:

http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It was indeed quite expensive. I got a pallet of four for $60, but they cost a lot more new.

The ground is near electrical panel. I will check tonight to be sure.

Not sure what you mean, sorry.

I am confused, there is a ground at the receptacle and the UPS is grounded to that ground.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Don't remember if I made previous references to impedance. Yes, wall receptacle safety ground has low resistance. But it has higher impedance. Impedance created by things such as sharp wire bends, inside metallic conduit, splices, wire length, etc. Previous references to ground being 'less than 10 feet' were about wire impedance. Wall receptacle is just too far to be considered earth ground. It provides low resistance ground to conduct (60 Hz) AC electric. But it has too many junctions, too many bends, too bundled with other wires, and too long to be an effective earthing ground.
View those pictures of www.tvtower.com to appreciate your primary protection system.
Ignoramus32515 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tom, can you describe the scenario for a common mode transient.
Just what would happen and where to cause it.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Typically destructive common mode transient is lightning. Typically occurs about once every 8 years - a number that varies even within a town due to factors like geology, exposure, manmade objects like nearby pipelines, and frequency of thunderstorms. A location that has high number of CG strikes per thunderstorm is WV. Another common mode transient can be generated by AC power switching by the utility.
Items frequently blamed for destructive transients such as washing machine or refrigerator, instead, create noise. Noise that is easily made irrelevant even by circuits in dimmer switches, GFCIs, and electronic power supplies. If appliances created destructive surges, then we all would be trooping weekly to hardware stores to replace dimmer switches, GFCIs, ... and those appliances.
CG lightning is a connection from the cloud to earthborne charges. Lightning forms a plasma wire that connects cloud charges, via lightning bolt and earth, to earthborne charges that may even be kilometers away from that 'at risk' household. Transistors are damaged when that electrical circuit passes through transistors which explains why one appliance might be damaged and an adjacent appliance remains unaffected.
BTW, one of the more interesting protection methods involves white pines that are located on the oncoming storm side. The author cites observations that white pine tends to perform like Franklin lightning rods to protect those below.
Ignoramus16420 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK. What do you mean by common mode: the occurrence of high voltage between the hot legs and electrical circuit ground? I do not think that it would be referred to as common mode in electronics.
Or do you mean occurrence of high voltage between the ground in the circuit as well as hots and neutral, vs. true earth ground?

The above does not explain what common mode transient is, it just says how often it occurs and when.
What I want is some clear understanding of what it is electrically. Just what voltages (potentials) become high in relation to what references.

A lightning striking outside cannot meaningfully raise potential of circuit neutral (which is tied to local ground at the panel, and that's where electricity comes from outside), it can only raise potential of the hots.
If so, I am not sure if that would be properly called a common mode transient, for devices that feed from the difference between potentials of hots and neutral, like consumer electronics.
Am I missing something?
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Common mode, from a building's perspective, is a current that seeks earth ground. Common mode, from appliance perspective is a current incoming (same direction) on any one or all wires of that port or cable, then outgoing on any one or all wires of another port.
From an appliance perspective, common mode means current on multiple wires moving in the same direction whereas normal mode is current incoming on one wire and outgoing on its mate. Common mode means current seeks earth - the common ground. Normal mode does not care whether earth is or is not of that path.
Current can change potential of a neutral wire where that end of wire is not connected to earth ground. Again, impedance. Assume a wall receptacle maybe 50 feet from the breaker box. That wire may have less than 0.2 ohms resistance, but may have as much as 120 ohms impedance. At the wall receptacle, a trivial 100 amp surge would put a wall receptacle at something less than 12,000 volts in relation to the wire's other earthed end. (Actual voltage would be far lower for other reasons.) Even if far end of a neutral wire is earthed, the receptacle end of that same neutral wire can carry a transient incoming to the appliance, as demonstrated by a previous example using the adjacent plug-in protector.
How often a transient occurs is part of an answer to another question, "Just what would happen and where to cause it."
Ignoramus16420 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ignoramus32515 wrote:

Have you checked the current draw of that furnace??? That power supply has a max of 1600W and at that it is only good for less than 10 minutes.
--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I have not checked it in detail, but I think that all that the furnace has is a bunch of electronics, gas valves, and 1/3 HP blower motor. Should be easily run off the 2200 VA UPS.
Am I missing something? Thanks
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ignoramus32515 wrote:

A 1/3 HP can draw over 7 amps and that would give you about 20 minutes max run time with a battery still having full capacity, batteries loose capacity as the age. I would say you would be lucky to get 10 minutes out of it.
--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

1/3 HP draws about 2 amps continuously, and more only momentarily, at startup. I can always verify it with a amp meter, but I would be surprised to see a big difference.
If the battery pack in the APC UPS has a 12 AH capacity at 48 volts, that translates to about 4.6 hours at 125 volts and 1 amp. Reducing that to allow for power losses to 3 AH at 125 volts, I can see that I can run this motor for about 1.5 hours. Even 1 hour would be fantastic, and looks achievable. I will also put my networking stuff on the UPS, which would add perhaps 100 watts at the very most.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Reducing that to allow for power losses to 3 AH at 125 volts, I can see that I can run this motor for about 1.5 hours. Even 1 hour would be fantastic"
What fantastic news! You can run your furnace for a whopping whole hour in a power outage. I'm beginning to see where your screen name came from.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I think that you are a victim of making too many assumptions.
I corrected a statement about an amp draw of a 1/3 HP motor and how long it could run on a APC 2200 UPS.
I see no reason to become sarcastic and somehow invoke my screen name, because of that correction.
Mind you, I have a generator that I could use, actually a very nice one.
http://igor.chudov.com/tmp/onan/Diesel /
It is nice though, for short term outages, not to need to do go out and start it.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"43. Ignoramus32515 Dec 21, 10:19 am
I see no reason to become sarcastic and somehow invoke my screen name, because of that correction. "
You chose the screen name, not me. You came in here pointing out that lightning had hit a tree near your house and you wanted to use a UPS for surge protection. Several of us have pointed out to you that a surge protector located in a UPS somewhere in the house is ineffective. For a surge protector to be really effective, lightning needs to be earthed to ground through a short path. Look at any industiral facility, or even the TV cable service that enters your house and you will see that surge protection is placed close to entry with as short a ground path as possible. A UPS used as a surge protector located a long way from an earth ground isn't going to be anywhere near as effective as installing a whole house surge protector. Plus, the whole house unit will protect everything in the house. But thqt apparently went right over your head.
And now you no longer appear concerned about lightning at all. Instead you want to use a UPS to back up a furnace? Even if you can run it for an hour, very few people would think it's worth the trouble. Even if I got if for free, I'd sell the UPS on Ebay, and use the money for real lightning protection. But then you sound like the guy with the big TV that listens to the kids in the store that tell you how you need the oxygen free $100 cables for the digital interconnect components. Did you buy the extended warranty too?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Yes. So, I agreed that I need other forms of surge protection.

The question I asked concerned redesign of my house's electricals to suit my new needs, and the issue of UPSes concerned more than surge protection.
And, by the way, this UPS does protect loads from surges and lightnings. It is not useless.
http://www.apcc.com/products/family/index.cfm?id 5&tabatures
``Protects connected loads from surges, spikes, lightning, and other power disturbances.''

Remember that a furnace does not run continuously. An hour of runtime, depending on ambient temperature, may translate into much longer time if the unit only runs intermittently.

I did not buy the extended warranty or monster cables.
You are beating a dead horse here, falsely implying that I do not want to use whole house surge protection.
The UPSes would not fetch much on ebay because even though at least 3 out of 4 seem to work, they are missing some front panels. I will sell at least one, but can make good use of at least two and see nothing ignorant about what I plan to do with UPSes. I could not care less if my UPSes are missing panels, they will be in the furnace room anyway.
If you have a suggestion about a particular whole house surge protector, I will be happy to listen.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Actually, plug-in UPS does not protect from typical surges and lightning. To do so means it must have a less than 10 foot connection to earth ground. Manufacturer claims protection for a typically nonexistent type of surge ... so that you will assume it protects from all types of surges. Plug-in UPSes have only one function - maintain power during blackouts and extreme brownouts.
Where in that APC site are specific numbers for protection from each type of transient? They don't make that claim. In previous times, APC would claim protection from only normal mode transients. Now they pretend all transients are same - make no mention of each mode of transient - so that one will assume all transients are the same mode.
Again for loads that are not electronic devices, be concerned with another number that the UPS should have provided - THD. You may need a number of 5% or less.
Ignoramus32515 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You made me confused here.
There are basically two kinds of events that can damage electronics:
1) power surge between hot and neutral. Which is fully taken care of by the UPS. 880 joules clamping power, see
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
2) a sudden common mode voltage surge between neutral/ground conductor and whatever is the other path to ground for the devices. This is a rare event at best, since conduit does provide a path to ground and could only have high voltage at the receptacle if directly hit by thousands of amps of current passing from the receptacle to ground.
And most home equipment, normally, is set on wooden furniture and does not have any alternate path to ground.
This is basically a scenario of lightning striking the house directly, and not only that, but entering through the receptacle that I am trying to protect.
An extreme rarity.
I would like you to clarify the scenario that you are referring to, as I have a hard time visualizing just what exactly you are referring to that UPSes do not protect against.

I would like to hear a little more detail on the exact mode of transient that you are referring to.

My UPS provides uner 5% THD, see the spec sheet I mentioned.
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
I appreciate your comments.
i

--


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The most common and destructive surge is common mode. In common mode surges, even wood, linoleum tile, and concrete become conductors. The fact that so many different circuits can exist is but another reason why we want the transient earthed outside the building AND why we prefer the earth to be equipotential - which is why Ufer grounds would be so useful.
The surge between hot and neutral is eliminated by a 'whole house' protector, typically does not exist, and is made irrelevant by protection already inside appliances. A typically destructive surge is common mode. Effective protectors for common mode transients also makes other transients irrelevant.
Don't let this idea grab you - that a protector will sit between the appliance and the transient source - blocking, stopping, or absorbing the transient. That just does not happen. Effective protection that even protects that telco switching computer works better when distant from electronics. Telcos prefer a 'whole house' protector on each incoming wire to be 50 meters from the electronics. Protection adjacent to the electronics - it's already inside the electronics.
Defined by effective protectors are protection from all types of transients. The APC unit only claimed to protect from normal mode transients. Now they even forget to mention which mode they protect from.
But lets see the spec for that APC protection that no longer even mentions normal mode: Surge energy rating 880 Joules Filtering Full time multi-pole noise filtering : 0.3% IEEE surge let-through : zero clamping response time : meets UL 1449
This is what they used to provide. At least they once provide more (but incomplete) information: Normal mode clamping response time 0 ns, instantaneous Normal mode surge voltage let through <5% of test peak voltage when subjected to IEEE 587 Cat. A 6kVA test Normal mode noise suppression Full time EMI/RFI filtering Modem/10Base-T/100Base-Tx network cable port single line (2 wire, RJ11) or network (UTP, RJ45) compatible jacks
They don't even provide a let-through voltage number. And where is the THD number. A number to define how much of a sine wave is really a sine wave. They make no reference to any mode of surge. It has no dedicated earth ground which suggests no effective common mode protection - the typically most destructive type of transient.
Ignoramus32515 wrote:

http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200NET&CFID $72096&CFTOKENS038870
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Would that common mode surge be a event where voltages of both hot, neutral as well as ground rise too much above true ground potential (potential of a copper rod buried in ground)?
Am I correctly describing what you have in mind?
If not, just what is it exactly?
I want to make sure that I understand exactly what you mean.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.