Residential Surge Protection

[mhulbert]

Hello,
I've been reaing this forum for a while but I am a new member. This is a great resource, makes one think about a lot of differnet installations.

I have a home owner that is interested in having whole house surge protection, and I'm trying to see what the best way to do this is. He has a LOT of electronics/computers, most that are used for his home based business. So, he's prepared to spend some money on this. We've already had one computer power supplied during the southern CA rotating blackouts last summer. He is buying 2-3 more computers and I need to make sure that we no longer have a surge issue.

I'm looking at some of the units put out by Wiremold ( Here ) . Intermatic makes something similiar but I'm not sure that these are enough. WOuld I gain anything by going to one of these companies larger systems, with the plug in modules and such? Also,how much effectiveness will I lose in respect to the length of the leads? The unit would be installed on the inside wall behind the main panel, so it would be a 12-20" lead length between the unit and the breaker feeding it. I was also thinking of augmenting the main unit by putting in the outlets with built in surge protection that serve computers/electronics. What am I missing here? Any other ideas or methods that I should be thinking of? Eventually, he will put the computer(s) on UPS's, but 3-5 of them would add up.
Thank you for any help,
Mike

 

[dereckbc]

Re: Residential Surge Protection

Mike I design a lot of TVSS for telephone companies and here is what I suggest in the preferred order.

1. If the service is 200 amps or less have the POCO install a Calss "C" TVSS at the meter base, or replace the main panel with built in TVSS..

2. Install a Calss "C" add on device beside the main panel and keep the leads to 6 inches or less. Any more than 6 inches renders the device useless.

Make sure the device has a UL-1449 Second edition rating with a SVR of 330 volts. AVOID CHEAP UNITS, you will get what you pay for.

Only buy devices with L-N modes only, do not waist money on multi-mode devices with L-G, and N-G modes. Buy as large as a unit as your client can afford.

Then follow up with Class "A" devices installed where used such as recpts with built-in TVSS.

I will be happy to answer any follow up question you may have.

[ February 26, 2004, 07:01 PM: Message edited by: dereckbc ]

 

[tom baker]

Re: Residential Surge Protection

Dereck what if the POCO won't allow a TVSS at the meter, and using one built in is not an option?

 

[dereckbc]

Re: Residential Surge Protection

The meter TVSS is supplied by the utility. It's a collar that the meter plugs into. You pull the meter, plug in the collar, then plug in the meter. In my area they charge a $25 installation fee and $5 a month. It comes with a $50K guarantee to replace major appliances like HVAC, micro, frig, hot water heater, etc, but not electronics. It comes with a indicator light and free replacement if it fails. If you want a $50K guarantee on electronics they offer recepts at point of use cheap, $5 dollar installed and $1 a month per unit. I have the meter type unit on my home, use dual conversion UPS on my PC, and balanced power system on A/V equipment.

If you cannot get one built into the main panel or a meter type, use a add on(parallel unit)as mentioned in option 2.

[ February 26, 2004, 08:07 PM: Message edited by: dereckbc ]

 

[charlie]

Re: Residential Surge Protection

Check out our Goldbook, Section 557 INSTALLATION OF TRANSIENT VOLTAGE SURGE SUPPRESSOR AND OTHER DEVICES AT METER SOCKETS
The installation of any meter adapter surge suppressor or any similar interface devices between the meter and meter socket is not acceptable and prohibited. If any surge suppressor or other similar interface device such as a generator connection, is found installed between the meter and meter fitting, Company field personnel will remove the device.

We do not permit any device between our meter and meter fitting.

 

[dereckbc]

Re: Residential Surge Protection

Charlie, I understand why the utility would not permit the customer too add their own TVSS device, but I am referring to a utility owned and operated device.

I assume from your statement IPL does not offer such a service to its customers.

 

[wbush]

Re: Residential Surge Protection

Regarding the IPALCO restriction on the use of a TVSS at meter location: Does this mean there can never be a Class C TVSS installed at the meter even by IPALCO? If so, what does IPALCO suggest for the customer desiring a Class C TVSS installation? Does IPALCO have a whole-house TVSS program it markets to the customer? If so, how do they handle the Class C location? What is it about the meter-socket installation that IPALCO finds objectionable?

 

[wbush]

Re: Residential Surge Protection

Dereck: I understand you recommend utilizing only L-L or L-N protection modes at the Class C location (IEEE C62.45 1991 reference to majority of incoming surge is normal mode?). Unless I'm mistaken (could be), IEEE C62.45 1991 recommends protection in all modes for Classes A, B and C. Do you have an industry reference to support your position? Or is your position based upon historical finding? Any comments or explanations or tutorial?

I might add I find your postings useful. keep up the good work.

 

[ron]

Re: Residential Surge Protection

At the service, a device that protects L-N and L-G is a wasted mode, as the two are married at that point. There is no loss in functionality, just a waste of money.

BTW, a class C device could be placed anywhere in the distribution system, not only at the meter. A Class C works very well at many distribution boards throughout the system as may be required by the designer. Just don't overdo it, with an expensive Class C where it is not warranted.

 

[dereckbc]

Re: Residential Surge Protection

Wbush, I base my statement made on R&D I performed when working for a Telco during the late 80?s and early 90?s while developing a TVSS product line manufactured by ACT, now owned by GE under the Tranquell Line. Rather than all the boring details here is the short answer.

As you mentioned 97% of all transients occur ahead of the transformer on the primary side. Which means the transients appears on the output as normal or differential mode rather than common mode. The minimum CMNR of utility transformers ranges between 40-to-50 db and higher. For those rare 3% that happen at the secondary, such as a direct strike, is still not a problem because of the main bonding jumper (MBJ) connected N-G at the service entrance

The main bonding jumper can dissipate much higher levels of energy than any given number of MOV?s or SAD?s devices installed across the MBJ. So there is no need for a TVSS device in the N-G mode at a service entrance.

The L-G mode at the service entrance is only redundant to the parallel L-N TVSS devices. They are in parallel because of the MBJ connecting N-G at the service entrance. So you are better off investing money in units that only have L-N modes at the service entrance. The redundant modes (L-G, & N-G) only add cost to the unit, and add no more protection. So my advice is buy only L-N modes and spend the extra in larger L-N modules rather than additional L-G and N-G modes.

Now for Class B & A devices there may be some benefit for N-G mode devices in large facilities where transients can be generated internally. As for residential, little or no chance of N-G events. I personally do not recommend N-G modes because any properly engineered device should not have any circuitry installed N-G, and any leakage would put load current on the EGC. However there are some consumer electronic products that install filters, MOV?s and such between N-G, but IMO that is a poor design asking for polarity and operational problems.

I would never recommend L-G mode for any class in any application as it serves no purpose and only leaks load current on the EGC circuits.

 

[charlie]

Re: Residential Surge Protection

We do not, nor do we intend to offer TVSS at the meter. We are staying out of the way of electrical contractors who wish to get into the business.

It seems that most are using the TVSS devices that take up circuit breaker positions in the main panelboards and supplementing with high end strips at the protected equipment. Additionally, the entire grounding system is looked for Code compliance and to verify single point grounding.

 

[dereckbc]

Re: Residential Surge Protection

Originally posted by charlie:
Additionally, the entire grounding system is looked for Code compliance and to verify single point grounding.

SPG, now that is funny. Not feasible in residential , industrial, or comerrcial applications, and even harder to maintain.

 

[dereckbc]

Re: Residential Surge Protection

Originally posted by charlie:
It seems that most are using the TVSS devices that take up circuit breaker positions in the main

Any one have any links for these devices? I have not used them and am very curious and skeptical of them. Their size would severly limit what you could put in them. I cannot imagine a a 160KA Class C or Class B in a breaker. I can see how the could be used in a sub-panel for a 8KA Class A device.

 

[mhulbert]

Re: Residential Surge Protection

DerekBC,
Thank you for the quick response. I am going to see if So CA Edison offers a unit or serivice like the meter collar you mentioned.

In case they don't, what companies have Class C devices that offer only the L-N protection only. The only comapnies I have looked at are Intermatic and Wiremold, and they only offer all-mode protection. What other comanies are out there?. Also, is it advantagous to install the breaker for the surge device at the top of the panel (assuming a top-fed panel here) so that it catches the surge before it moves further down the busbars to the rest of the branch circuit breakers??

With a Class C device on a residential service, meter collar or add-on unit, do you think it's neccesary to use the outlets with built in TVSS in them. Seems like cheap insurance for electronics, but no sense installing without a reason.

Thank you again for the help,
Mike

 

[mhulbert]

Re: Residential Surge Protection

I just found one from Square D for QO and Homeline:
Here

Originally posted by dereckbc:

Originally posted by charlie:
It seems that most are using the TVSS devices that take up circuit breaker positions in the main

Any one have any links for these devices? I have not used them and am very curious and skeptical of them. Their size would severly limit what you could put in them. I cannot imagine a a 160KA Class C or Class B in a breaker. I can see how the could be used in a sub-panel for a 8KA Class A device.

 

[dereckbc]

Re: Residential Surge Protection

Originally posted by mhulbert:
What other companies are out there?. Also, is it advantageous to install the breaker for the surge device at the top of the panel (assuming a top-fed panel here) so that it catches the surge before it moves further down the busbars to the rest of the branch circuit breakers??

With a Class C device on a residential service, meter collar or add-on unit, do you think it's necessary to use the outlets with built in TVSS in them. Seems like cheap insurance for electronics, but no sense installing without a reason.

There are many companies out there that make TVSS. Stick with names you know and trust like GE, Leviton, Northern Technologies, etc. I do not do residential, so maybe other members can drop some names. The key is looking into the specs. Here are the specs of one I participated in developing http://www.geindustrial.com/cwc/products?pnlid=5&famid=37&catid=85&id=tvssoem&typeId=4&lang=en_US Then click on FES 133. This unit is way more than a residence needs, but you will get the idea. You want to see the UL-1449 Second Edition SVR rating. The best is 330 VAC for single phase service, typical is 400. The only SVR 330 units I have seen are built into the service panel or meter sockets. The lower the better. Also you want to look at what ANSI categories (Cat 3 is the meanest, nastiest used) pulses were used to test with and how many without MOV degration. If they fail to list this info, walk away. It will not be cheap.

A good spec for a residential application would be something like:
40-60KA per mode.
Tested/Listed UL 1449 Second Edition SVR = 400
Tested with 3000-5000 ANSI Cat B-2 pulses with less than 10% MOV degration.

Always try to install the breaker as close to the top or near to the entrance as possible. If the leads exceed 6 inches, you will severely degrade the SVR rating. The SVR rating is the clamping voltage of the fully assembled unit with 6 inches of leads. You can add about 100 volts to the SVR for every inch past 6 inches.

For added protection it is wise to add point-of-use TVSS devices on sensitive equipment, but not necessary if you have a quality device on the entrance. There cheap, I use them. You can get very well made devices for around $35 and up. Many with recognized names offer very good guarantess against equipment damage.

 

[charlie]

Re: Residential Surge Protection

SPG, now that is funny. Not feasible in residential , industrial, or commercial applications, and even harder to maintain.

Dereck, I don't understand this comment. CATV and telephone have sometimes entered a building without connecting their pitiful grounding to the power grounding. This results in multiple paths to ground for surges and they are through electronic equipment. These have to be connected together to get a single electrode in order for the system to work correctly.

Why is it not feasible to be done?

 

[dereckbc]

Re: Residential Surge Protection

Originally posted by charlie:

Why is it not feasible to be done?

Charlie, it depends on how you interpret single point grounding. Since I am in the telecom/data, it has two meanings.

One is Single Point Grounding for Frames: A method used to ground a set of frames for a given electronic entity that can have only one grounding connection from the given set of frames to a planned reference point. Because this set of frames does not have multiconnections (either planned or incidental) to other ground references, it is classified as an Isolated Ground Plane. In order to be an Isolated Ground Plane there cannot be any planned or incidental contact with raceways, concrete, rebar, structural steel. The equipment and raceways are installed with isolators. Electrically it is floating in the air with only one ground connection. No external currents can flow in or out.

The other is Single-Point-Ground for power supplies. Where one current-carrying member of a SDS power source is connected to a ground reference at only one point.

To complete the single point ground a ?Ground Window? is establish and a ground bar is installed in the ground window to reference the frames and power source. Both are kept completely isolated from what I call the integrated ground plane (rebar, structural steel, concrete, etc.).

 

[charlie]

Re: Residential Surge Protection

Dereck, when I taught apprentice electricians, I insisted on using the correct terminology for everything. For instance the term Romex was not acceptable for NM cable. The end result was apprentices that could go anywhere and understand what other people were talking about.

This is the first time I have heard either of the definitions of SPG that was different than the one I know about and is reflected in 250.58. Although I had taught this as the single point grounding concept, the only place in the Code that single point is mentioned is 690.42.

It looks like the next time I teach a grounding class that I will be required to explain what I mean is the single electrode concept instead of the single point grounding concept.

 

[dereckbc]

Re: Residential Surge Protection

Charlie, I do not think what you have taught is wrong. IMO there are two types of grounding, "Safety" and "Performance".

Safety grounding is the realm of NEC, and is included in what I call the "Integrated Ground Plane". You have your planned fault clearing path (EGC) plus other unplanned (incidental) paths which include concrete, structural steel, rebar, equipment frames, raceways, earth, etc. It's purpose is strictly for life and fire safety.

Performance grounding is the realm of equipment engineers. "Isolated Ground Planes" and "SPG" are just some of the performance methods. Performance grounding meets NEC (safety) requirements, but exceeds in operational characteristics. I am certain you have dealt with performance grounding by using grids in sub-stations.