Surge Protector on BOTH Main and Sub-panel?

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Old 06-24-08, 12:30 PM
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Question Surge Protector on BOTH Main and Sub-panel?

Is there any reason to limit the use of a whole house surge protector to JUST the main panel?

We had our main panel replaced and the electrician installed a Siemens QSA2020 TVSS whole whole protector in the new panel. (This took the place of an Intermatic IG1240RC whole house protector that had been on the old main panel.)

I have a 100 AMP sub-panel for my workshop which has a 5 HP dust collector (yet to be installed) that is rated 21.8 FLA on a 240 V circuit. The retailer tells me that there is a momentary draw of 105 AMPs for less than 1/2 second, though the continuous draw under typical use is about 16 AMPs. No doubt this device , alone, can cause some significant momentary surges in the rest of the house.

I do use a tiered system of surge protection in the house with UPS/surge protection for the computers and individual plug in receptacle type surge protectors for other sensitive electronics at the point of use.

Is there any reason that I should NOT install my old Intermatic IG1240RC whole house TVSS in the SUB-panel when I already have the QSA2020 in the MAIN panel?

Thank you in advance for your education and insights that can help me and others, Chuck
 
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  #2  
Old 06-24-08, 01:21 PM
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surge protector won't stop voltage sag

due to motor startup. If you have electronic equipment fed from the sub, then i'd consider a 2nd TVSS.

Surge= momentary, over a few PLC (power line cycles)INCREASE in voltage
Sag= momentary, over tens of milliseconds DECREASE in voltage
Spike= very short INCREASE in voltage, less than a PLC
Brownout= very long DECREASE in voltage
Dropout= momentary ELIMINATION of voltage

your TVSS handle many (not all) Spike conditions, that's it...
 
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Old 06-24-08, 02:45 PM
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Never having seen data. . .

on the likelihood of equipment failure before installing surge protectors

and the likelihood of equipment failure after installing surge protectors,

I think they somewhat have the smell of snake oil (except for the stuff Ma Bell uses to protect their phone lines).

But, they sell like hotcakes.

It would take one muvva' of a surge to get past the input to the switching power supply in your computer.
Incandescent lamps don't care about reasonably short surges.
Motors/relays less so.

Implied Merchantability and the lawsuits over them drives manufacturers to make their equipment reasonably hardy.

If your computer costs $2000 and the surge protector costs $20, it would make sense to buy one if the likelihood [that it could protect your computer in the face of the surge that may someday come] was >20/2000.
I don't know what this likelihood is, and I don't think any surge protector manufacturer is interested in finding out.

It's about as easy as finding out the likelihood that your house will flood by asking the companies that sell flood insurance. But you can bet they know this number to three decimal places because it's their money riding on this gamble.
 
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Old 06-24-08, 07:15 PM
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I must respectfully disagree with the "snake oil" comment when it comes to surge protection.
There is no more reasonable investment that you can make when it comes to your electrical service (unless of course it needs repair).
With the proliferation of equipment in our homes that are chip based, surge protection cannot be emphasized enough.
I don't know where WDIBAA lives but obviously it is not in a hurricane or lightning zone such as South Florida.
Hardly a storm goes by that we don't hear from someone whose refrigerator or stove or TV has quit working.
It will almost always turn out to be damaged electronic components.
If I had stocked up on boards for SubZero refrigerators during the last hurricane, I would not be sitting here writing this because I would have been able to retire to the islands.

See this link for more info on surge protection
http://www.surgeassure.com/learnmore.aspx
 

Last edited by dezwit; 06-24-08 at 07:32 PM.
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Old 06-25-08, 08:28 AM
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"snake oil"

Objection noted.
Can you then give us specs on surge protectors that will usually or always prevent damage to the components you mentioned, so we don't "overbuy"? If it works for lightning it will certainly work for "dirty" power.

My likelihood thing was wrong.
If your $2000 computer over its 5 year life has a 1% chance of getting a fatal surge, you should spend no more than $20 on a protector for it.

Where you are the likelihood seems to approach 100%, so, something else occurs to me. I have seen circuits for detecting lightning storms in the vicinity. Any AM radio will peform this function.
Maybe someone makes such a device hooked to relays that cuts the power to sensitive equipment, rather than trying to absorb all those joules and kilovolts.
The concept is simple enough but there might be practical problems in implementing it.
 
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Old 06-25-08, 11:08 AM
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"Dirty power" and lightning are two completely different animals and must be protected against with different solutions.

Dirty power has a unique definition to everyone. To me it refers to a distorted waveform and the solution to that is a power conditioner such as a true sine wave online UPS for small loads or a motor generator set with a flywheel for large industrial loads. Neither solutions are cheap and are tough to economically justify.

The solution to lightning/surge protection is bonding of all grounding systems together along with surge suppression and there are multiple methods and degrees of surge protection one can implement, again based on how much one can justify spending.

Your AM radio idea is interesting, but I see a possible problem with false positives caused by electric utility equipment giving off radio frequency interference.
 
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Old 06-25-08, 11:36 AM
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I read the surgeassure link. The people who wrote that were fairly oily, I'd say, but they are also far removed from the factory floor.
Didn't much like their collaboration with other industries.
http://en.wikipedia.org/wiki/Revolving_door_(politics)

I don't disagree with what they said, but you are, after all, buying insurance. I'd ask for the before and after stats and the cost. It's hard to spin numbers, but I've seen it done.
Uncertainty works in favor of the vendor.

Adults make decisions for kids because the kids are not equipped to. Once you have the data you can make the decision, as is your right as an adult.
Withholding the data puts you in the position of the surge people making your decisons for you; they are the "mommy" and you are the kid.

Speaking of uncertainty, recommended reading for anyone in this country is "unSpun: Finding Facts in a World of Disinformation by Brooks Jackson and Kathleen Hall Jamieson". Also, the book on lies by Eckman.

Re: dirty power, keeping me honest is a full time job.
The best system would be adaptive, probably using a neural network that learns the hazards local to your area and gives you protection to a 95% or 99% confidence level. There might already be patents in the works for this.

I don't have surge protection but I am 1500' from a radio tower. Let them attract, and pay for, taking these hits. The more inductance, capacitance and resistance that is between my stuff and the lightning strike, the better.
 

Last edited by WDIBAA; 06-25-08 at 11:37 AM. Reason: reads better
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Old 06-25-08, 11:49 AM
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Originally Posted by ChuckR600 View Post

Is there any reason that I should NOT install my old Intermatic IG1240RC whole house TVSS in the SUB-panel when I already have the QSA2020 in the MAIN panel?

Thank you in advance for your education and insights that can help me and others, Chuck

Look for the initial clamping voltage on your old and new surge protector. If the initial clamping voltages are the same, then putting your old one on a subpanel will not really provide any additional protection. At best it will provide backup surge protection to that subpanel if your new surge protector at your main should fail.
 
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Old 06-25-08, 02:41 PM
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Originally Posted by WDIBAA View Post
Maybe someone makes such a device hooked to relays that cuts the power to sensitive equipment, rather than trying to absorb all those joules and kilovolts.
The concept is simple enough but there might be practical problems in implementing it.
Trouble is, almost all modern appliances have "sensitive electronics". You mention the computer. Your computer power supply passes the test for CE spec line surge and spikes, Electrical Fast Transient testing already, WITHOUT an external TVSS. BUT, what about that 2 year old dishwasher, the new oven with digital display, the furnace multi-speed blower, etc. Many new things in your home that now have electronics and did not 15 or 10 years ago. AND, they are running on 240v, not very convenient for local TVSS (surge strip protection). Few medium and high end appliances use mechanical timers any more. A clock/timer can take a huge surge and be unscathed. Any guess what is doing the timing / control now?
 
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Old 06-25-08, 02:45 PM
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Originally Posted by WDIBAA View Post
I don't have surge protection but I am 1500' from a radio tower. Let them attract, and pay for, taking these hits. The more inductance, capacitance and resistance that is between my stuff and the lightning strike, the better.
There are reports of lighnting hits and damage on equipment under the shadow of very high antennas. Your call.
 
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Old 06-25-08, 05:21 PM
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I self-insure when I can, so I save whatever profit margin the insurance company makes. They've already done the cost/risk calc and so they charge you
(the replacement cost) x (the likelihood that they will need to replace it) + their overhead, etc.
When I can't self-insure I use high deductibles.
We're talking only property damage here; human safety and mutilating injuries and juries and such is a whole 'nother ball game.

Since I fix/design my own stuff the risk equation gets skewed somewhat in my favor.

And I did search out and get a dishwasher with a mechanical timer (the old [two year old] piece of excrement is in the basement waiting on my new sequencer design, but I'm not holding my breath).

I've never had a failure due to power surges in NJ or MD, but maybe that means I'm due one, and it definitely means I'm biased.
http://en.wikipedia.org/wiki/Risk_aversion

I'm thinking the current political climate is reducing the Implied Merchantibility burden on the manufacturers, so the first thing that goes is reliability. It's sad.
Plus all the bells and whistles that we never asked for gives them a reason to charge out the wazoo (sp?).
 
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