Safety Alert - Surge Protector Linked to House Fires

Thank you for the advise I will pass this on to HVAC contractors in the neighborhood.

To whom it may concern: The Sycom T2 unit was not involved in the Cary incidents or any other instances of fires. The Supco SCM 150 was the named product in these cases. Research indicates that the fire situations occurred due to a grounding issue, not a manufacturer defect or design flaw. Only when installed to the AC disconnect on residential applications. When resistance to ground is too high where installed, (with a shunting device such as these)a surge can cause heat to build in the units. This is not limited to Sycom or Supco units, this is a rule for all shunt-to-ground type surge protectors. The NEC maximum resistance at ground for shunt-to-ground surge protectors is 25Ohms or less. Any variation of this requirement can cause performance issues. This is a installation problem not a defect or design flaw. Sycom has worked with UL on a voluntary replacement program (approved by UL) since July of 2016. The program ended on 1/1/2019. We suggest any concerned contractors or home owners to check the ground resistance at the point of installation.

Thank you, Sycom Management

• Reply from: Mike Holt   January 18 2019, 3:50 pm EST
  The earth ground resistance has nothing to do with the performance of surge protection devices. There is no NEC 25 ohms ground resistance requirement.
  Reply to Mike Holt

  • Reply from: Charlene   January 18 2019, 7:27 pm EST
    Mike,

    When did the 25ohm requirement get pulled from NEC?

    Thank you, Charlene
    Reply to Charlene

    • Reply from: Mike Holt   January 20 2019, 6:56 pm EST
      There has never been a minimum NEC ground resistance in the NEC, and ground resistance has nothing to do with surge protection performance or lack of performance...
      Reply to Mike Holt

    • Reply from: Charlene Mobsby   January 21 2019, 9:10 pm EST
      To my knowledge, all new house grounds require 25ohms or less, otherwise, you have to drive another rod
      Reply to Charlene Mobsby

      • Reply from: Mike Holt   January 21 2019, 9:51 pm EST
        Correct, but if the one ground rod is 100 ohms, then driving another 100 ohm ground is fine (total resistance of 50 ohms).
        Reply to Mike Holt

  • Reply from: Roger Leavitt   January 19 2019, 3:29 pm EST
    Don't surges from lightning seek the earth rather than the utility neutral? Seems like a low resistance path to ground would help a surge protector do its job.
    Reply to Roger Leavitt

    • Reply from: Mike Holt   January 20 2019, 6:56 pm EST
      Not from a surge protector...
      Reply to Mike Holt

    • Reply from: Charlene Mobsby   January 21 2019, 9:09 pm EST
      That's exactly how surge protection works.

      All Surge protection diverts the over voltage to the ground, a must for Surge Protection.
      Reply to Charlene Mobsby

      • Reply from: Mike Holt   January 21 2019, 9:50 pm EST
        I'm sorry that you 'think' this is how surge protection works. If this is true, please do me a favor, draw up the circuit, add values that you feel apply, show me the direction of current into and out of the SPD. Show me, via the math, how you think the 'earth' impacts 'surge protection.'

        Now Surge Arrestors do shunt current to the earth, but that is a totally different topic. Surge Arrestors are not installed on premises wiring, they are for high-voltage systems, typically utility wiring. Suggestion: You might want to take this topic off-line so that you don't say anything else that is not true...
        Reply to Mike Holt

• Reply from: David Cameron   January 18 2019, 8:31 pm EST
  can you tell me where in the nec you find, The NEC maximum resistance at ground for shunt-to-ground surge protectors is 25 Ohms or less. thank you
  Reply to David Cameron

  • Reply from: Mike Holt   January 20 2019, 6:56 pm EST
    There is no such requirement.
    Reply to Mike Holt

This has me curious as to what other common denominators there may be: 1. Were all these units installed by the same installer, and possible incorrectly or not to best practices? 2. Is there something inherently wrong in the serving utilities grid in this area; are surges common or above an acceptable threshold? 3. Where were these units purchased, is it possible that they are counterfeit?

This is new? My company has been aware and actively replacing these units for more than two years. We have even had burned units in hand.

• Reply from: Bob   January 18 2019, 12:48 am EST
  Mike, who told you that an AC unit needs a surge protector of 10 amps? I never heard of such a thing in 60 years of experience working with AC units. The American built AC compressors start with LRA, always far more than 10 amps.Their is a foreign technology that can soft start compressors and I have such a unit but the manufacturer does not recommend a surge supresser.
  Reply to Bob

  • Reply from: Mike Holt   January 18 2019, 4:20 pm EST
    Bob, I don't understand your comment about 10 amperes? Where is that text?
    Reply to Mike Holt