Residential Surge Protection Using TVSS’s SPD’s Part II

June 7, 2009

damaged modemAn  analysis commissioned by State Farm Insurance found of 5500 detailed claims, more than half of the loss was related to telephone and electronic appliances.

As we become more connected through smart technology, AC power and low voltage or non-voltage carrying conductors become intertwined through the technology. When you think about it, more and more devices have an AC power cord  and a communications port for the transmission/reception of an external signal (video, DSL, etc.). Known as  “multi-port” equipment (AV Receivers, TV’s Modems, Computers, etc.) these devices add complexity to the transient voltage issue by creating additional doorways into the equipment. As we saw  in the AC Ground and Bonding article, external surges can enter the house as easily through the Telephone line, CATV or Satellite Dish as the AC utility. Studies show, even with a TVSS in the AC circuit, micro-electronics embedded in the equipment have failed due to transient voltages passing through the communications link. According to the same insurance study mentioned above, equipment including micro-electronics such as computers, TV’s, VCR’s and Satellite receivers recorded more significant losses than single-port equipment. This is not news to most of us. However, the point to recognize here is that any incoming services that arrive inside the house on a current carrying conductor (copper wire) has the potential to allow a voltage surge into the house and into our electronic equipment.

To make matters worse, having proper surge protection on the AC service and not on non-power related services may actually enhance the opportunity for a fault to occur in the multi-port equipment through surge current.  This  surge current  can create a  voltage shift  at the secondary-port on the equipment producing damage in the equipment. This voltage shift condition can also be rooted to a difference in voltage potential or ground reference at (you guessed it) the service entrance ground. This is the reason why we have seen more emphasis from the standards bodies (National Electric Code and National Institute of Standards Institute)  on the common grounding and bonding of all the incoming services (Telephone, CATV and Satellite TV) found in a typical residence. For this reason, in 1992 the IEEE  recognized this potential fault condition and coined the term Surge Reference Equalizer. Even though the industry has not really picked up on the term nor have they created a specific standard, the  UL1449 listing for this Class B surge protectors is acceptable for the time being.

 Proper Bonding and Grounding  Remain the Key Contributor to Both the Problem and the Solution

If you have read the four articles up to this point, you may think I am beating this subject to death, but grounding/bonding  remains the key contributor to both the problem and the solution. Complete the 8 point check list found in the AC Service Bond and Ground Part II.  If your house is less than 10 years old, it would be a fair assumption that all the incoming services enter near or at the AC service meter. Assuming all the services are bonded correctly as mentioned, you should be in good shape with the Telephone and CATV. For the rest of us, these services could attach any where around the house this also includes Satellite TV Antennas.  If possible, bringing all of these services within 20 feet of the AC Service entrance and attaching them as mentioned will assist in improving the ground system. (TIP: Satellite installations are typically located where they provide the best signal, bringing the ground termination from AC service entrance is important here as well).

Surge Reference Equalizer

surge protector class b 2At this point, we will assume that you have a good common ground with an equal ground reference. With that said you have successfully reduced the risk to multi-port equipment, BUT, both the IEEE and the NIST support the use of the Surge Reference Equalizer. As pictured, it looks like a typical Class B surge protector, but also has ports for communications ( RJ45 terminal, and threaded CATV terminal. With this type of TVSS there will be a PORT-IN and PORT-OUT set of connections.  Consider a Class B surge protector that includes both communication ports and CATV connections collectively in the same product for home theater equipment, set top boxes, satellite equipment, computers and any other mutli-port electrical equipment.  

Additionally Square D has release a whole house model that includes a Class C surge protector and the connections for Telco and CATV services. Tiered protection is still recommended if you decide to follow the whole house approach. (Square D Model SDSB1175C). NOTE: This method of reference equalizer is fairly new as previous practices supported keeping the services segregated until the point of termination, (CATV, Phone) independently until they reach the point of  use or the device that is common (i.e. TV, PC). As you will note, that is how I built my system. This is still an acceptable solution. 

Additional Choices – Surge Protection for Communication, CATV and Satellite:

Telephone Service: Most wire-line telephone service companies provide surge protection. If your telephone service was installed less NIDthan 10 years ago or has been worked on in that time frame you will probably have a NID (Network Interface Device) at the telephone entrance.  Telephone companies typically use “Gas filled arrestors”. Even though you may not have a NID, you probably have gas arrestors  if your phone  has been serviced in the last 20 years. Gas arrestors replace Carbon arrestors as the gas style will defeat the surge without a long term loss in service as they will self restore automatically. Since I built my grounding system before the Surge Reference Equalizer was readily available,  I placed an additional surge suppresor on my telephone line (Channel Vision C-0410). Much like the Telco provided unit it will disconnect the line in the event of a surge then restore it momentarily. Based on the performance characteristics of a Surge Reference Equalizer (SRE), in theory, I may still have a fault occur if my ground reference is not equalized and my Category A, B and C surge protectors are unable to defeat the surge prior to entering any of the protected equipment.  Since the current UL1449 is the only published document and it seems to favor an AC type failure,  for now, I am staying with my current system architecture using the C-0410  surge protection. TIP: You may have communications and/or video services provided by fiber optics. They will not have surge protection as optical services are unable to carry voltage or surge current.  If you are unsure if you have fiber optic services, the NID will have a consumer replaceable battery pack that you were informed about during the installation of the services.

4EDHICCAOT4EQ5CAS0S8SJCAJTJ6C8CATZJ50ECAZ5INCICAHEAI1MCAUYSD7KCAH7U0MDCAW5L3WSCA19XS37CAG3S3RACAVHVBMWCAXWUAI6CAED0UDWCAI9J2UFCAR71UZ8CA65BE4DCAQB2POKCATV and Satillite Services:In practice, the gas style arrestor  is used in these services as well. Because they use coax as a cable medium the arrestor looks a little different but perform in a similar fashion as the communications arrestor.

Theory vs. Science

One of the difficulties with this subject is it is very difficult to test your solution. To replicate a surge equivalent to a lightning strike is not feasible nor recommended. For this reason, surge protection, TVSS’s, SPD’s and bonding and grounding is not as black and white as we would like it to be and neither are the solutions. As you have seen in this article , there may be multiple solutions to the methods I have described. But overall, the method should still retain the same theme.   I have engineered large systems in multi story buildings and spent hundreds of thousands of dollars (not mine) to create the right grounding network  and still had recordable faults, so don’t think you will ever be 100% protected.  

One of the best articles written to date for residential bonding/grounding and surge protection is “Surges Happen”   produced by the Institute of Standards and Technology. This article covers the topic in very simple language and easy to understand instructions.

If you haven’t already, you may also want to read my 4 previous articles; AC Ground and Bonding, Electrical Switches and Outlets, AC Service Bond and Ground Part II, Residential AC Surge Protectors,

Key Inspection Points and Action Items:

  1. Annually check all your TVSS devices to insure the they remain in the protected mode (LED indicator).
  2. Follow the inspection routines as defined in AC Service Ground and Bonding Network by inspecting the mechanical connections and terminations.

In writing this series, it became apparent that I could not cover the subject in 1 or 2 postings. I hope I kept your attention and it made sense. Feel free to comment or send specific questions to Homeownerbob@gmail.com

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Residential AC Surge Protection Using SPD’s and TVSS’s

May 31, 2009

lightningNeither the IEEE (Institute for Electrical and Electronic Engineers) or ANSI (American National Standards Institute) recognize Joule Rating as a means to determine any level of surge protection.

The best way to deal with electrical surges and spikes is to divert them from entering the house in the first place. This is why the external ground system mentioned in Part II is so important. Spikes and surges look for the quickest and shortest path to ground.  Industry Standards recognize that creating a tiered or layered approach to transient voltage  management for your house will provide the best protection, but it’s still no guarantee. Lightning strikes and surges can appear to have their own mind when it comes to seeking ground.  Following the recommendations that I have mentioned in this series of articles will assist in properly protecting  you and your house.

Layered Approach to Surge Suppression

Approaching  surge protection with tiers serves to create layers of  filtering .  ANSI and IEEE acknowledge 3 tiers, A, B and C.  Each level is recognized to provide protection for a defined application. Look at the following drawing to visualize the different tiers and location of the protection device. Class C is located at the service entrance or meter, Class B serves sub-panels and points of distribution (power strips), and Class A provides protection at the source or point of use (POU).

 TVSSv2

Most whole house residential grade TVSS’s  (transient voltage surge suppressor) use MOV’s (metal oxide varistors) for protection. By design, the TVSS does not absorb the fault but divert it to ground. By doing so, these faults erode the MOV’s over time. For this reason, most high quality TVSS’s include some form of “wellness” indicator or failure alarm (red or green LED lamp). Once the MOV’s are destroyed, the lamp indicator is extinguished or in some cases sets off an alarm. Studies show these MOV equipped TVSS’s can last up to 10 years. Granted, this life expectancy is directly impacted by the number of spikes and surges diverted by the MOV’s. So if you live near me in Texas, Oklahoma or places with lots of lightning, don’t count on the 10 years of life. 

The IEEE  recognizes three classes of surge protection and they all perform a defined task, but regardless of the class, all the surge protectors should meet these standards.

  • Listed  with UL 1449 Second addition (not meets, complies or designed to). TIP: If a product is “listed” with UL, Underwriters Labratory actully tested it for compliance to the standard.
  • Comply with ANSI/IEEE C62.41 as it pertains to the class category (C, B or A)
  • SVR rating of 400V or less (probably the most important rating)
  • Per phase rating of 70,000A or less
  • TVSS shall protect against line to line, line to ground  and neutral to ground voltage transients
  • Include visual indicators (red or green LED) for proper operation or failure of the TVSS
  • Class C & B devices shall operate bi-directional and treat both positive and negative impulses, yielding line control and short fliker ride-through. If the Class A does this that’s good too, but more important in the Class B and C
  • In shopping for a TVSS (aka SPD or Surge Protection Device) look for this information on the box or possibly in the fine print with the instructions.

    Surge Protection Devices come in many shapes and sizes at each class allowing you different choices. If you choose to install a Class C unit, you may have to employe an electrician, otherwise  you can use plug-in modules for the other two levels. 

    Class C Whole House TVSS Suppressors for Service Entrance Applications: Intended to be located at the incoming AC service or AC service panel. For various reasons, there are multiple types and styles for Class C residential TVSS’s. Hopefully one of these styles can be integrated into you electrical system.

    8MLB34CAXTULUCCA683WXWCAZ9RMICCAAJD0LLCA2TBUMZCAJP70R2CAQBLV90CAXW8Z0KCAD3SO8UCAWLMVA8CAW85X0MCA09XOTYCAIKMTBACAXK0BG6CAGJA7AICA11C7C0CAZRGZN5CASXME2QMeter Base TVSS: In some municipalities the utility carrier may offer to sell or lease you this type of TVSS. Other than the fact they will probably want to charge you a monthly fee, I like the meter base style. This TVSS is placed in the circuit prior to entering the house service panel. This allows the TVSS to divert any external surge to ground prior to entering the AC Service Panel where a surge could go through the house instead of the intended ground source.   I spoke with my electric provider but they did not offer this service nor would they allow me to supply my own.

     Circuit Breaker Derived TVSS: With this design, the TVSS is wired into the house AC Service panel. Like most, it is equipped KGXLCICAK8YY0ACA4Y6SENCAT00S0QCA8ILWGGCAI4RG93CAPL7N6JCAIOLQEOCA89V8DICADV5D7SCAFP6C2ZCA6SSVLQCACWP20OCA0IU2YTCARFBJFUCAW6A4B2CABBYFDICAZGFPHTCAIU4OGSwith MOV’s and a state of health LED lamps. These styles can be purchased for both indoor and outdoor applications (indoor model pictured). The key here is to keep the TVSS installation as close as possible to the service panel and the connection wire should be as with the short as possible (6″ or less). For my house I also re-arranged my circuit breakers in the panel to allow me to place the TVSS circuit breakers as close to the incoming mains as possible. This is just a little added work to divert the surge as soon as it enters the panel. 

    QO Breaker TVSSAC Panel Based TVSS: Similar to the circuit breaker design previously mentioned. This breaker style TVSS consumes 2 breaker positions to provide panel protection. The advantage of this type is that it connects directly to the bus terminations in the AC Service panel. The disadvantage is that it consumes two positions and you may not be able to locate one that fits your AC service panel. 

    Power StripClass B  TVSS Suppressors for Distribution and Short Branch Circuits: As a classification the “B” type is recognized to serve electrical sub-panels and distribution, meaning a power strip with multiple outlet with a collection of devices to protect.   The Class B is the most common type found in electronics, computer stores and home centers. You will have numerous to choose from. Just remember to use the criteria listed above to  help with your choice. I would not use the joules rating as part of your decision making process.  Belkin surge protector

      Class A TVSS Point of Use Surge Protection Device for Outlet and Long Branch Circuits:  As a Class A TVSS, this device can either be an individual plug-in module (as pictured) or the outlet itself. I have used both and depending on the application the outlet version can be a better choice when you have limited space, such as behind a refrigerator or Plasma TV. Additionally, I found the outlet style more difficult to obtain and more than double the cost of the plug-in style. They both include the proper operation indicator. 

     By this point you should recognize two major points. 1)  Having proper grounding is imperative and, 2) surge suppression goes beyond point of use (POU) devices, 3) implementing a tiered approach is necessary to protect you and your household adequately. 

    Believe it or not…. there is still more. Next time I will discuss specific surge protection for your CATV and Telephone service.

    You may also want to read: Electrical Switches and Outlets, AC Service Ground and Bonding, AC Service Ground Part II,