Are surge suppressors bi-directional?

[Ira]

I understand the outlet strip surge suppressors are not "perfect", but I assume they are better than nothing, especially for situations where a UPS w/ surge protection isn't reasonable.

My question is...are they bi-directional? For example, let's say I have an irrigation controller power supply plugged into an outlet strip with surge suppression. I get a surge that originated in the irrigation zone wiring in my yard due to a nearby lightning strike (that doesn't cause a similar surge on my house wiring). So the direction of the surge is zone wires -> controller -> power supply -> outlet strip w/ SS -> home wiring.

Will the outlet strip with SS provide any protection to my home wiring (downstream) at all, or will it not do anything because the surge is going "in the wrong direction"?

Ira

 

[Del91574]

No, there's generally a protected side and unprotected side to any surge.

In your example, a hit/surge in your field wiring is likely to pop anything in line between that and your AC connection, however it isn't likely to travel further than that. A surge on the other side should be bled off via the surge/connection to ground.

You can surge the field wiring/devices using something that Ditek or Edco makes, we use their stuff all the time on fire alarm because of code requirements.

 

[mustangcoupe]

The suppressors in your basic inexpensive pluc strips are not directional, they typically use a mov for suppression which will will "short" above the rated voltage and shunt the surge. That being said in your example it will most likely damage the controller and maybe the power supply on it's path to the house wiring.

 

[Digger]

Alarm system devices have their input/output circuits typically protected by MOVS and or transzorbs. Some still even use spark gaps as well. If its UL Listed it has passed several different transient tests.

While that will protect the equipment from many commonly induced transients they dont do that much for lightning or near lightning hits.

Depending on the equipment design it is best to ground it or not. You have to see what the mfg reccommends. For the ELK M1 its best not to ground it as noted in their instructions. Most panels you would ground though.

The Ditek devices are very good but still you cant protect anything from lightning all of the time.

 

[hagak]

Alarm system devices have their input/output circuits typically protected by MOVS and or transzorbs. Some still even use spark gaps as well. If its UL Listed it has passed several different transient tests.

While that will protect the equipment from many commonly induced transients they dont do that much for lightning or near lightning hits.

Depending on the equipment design it is best to ground it or not. You have to see what the mfg reccommends. For the ELK M1 its best not to ground it as noted in their instructions. Most panels you would ground though.

The Ditek devices are very good but still you cant protect anything from lightning all of the time.

Curious about the grounding of the panel in regards to the Elk M1G. If you install a J-box to the panel wouldn't the panel have to be grounded to meet electrical code standards? Also I noticed that the Elk supplied panels all come with a green safety ground nut.

 

[Digger]

Curious about the grounding of the panel in regards to the Elk M1G. If you install a J-box to the panel wouldn't the panel have to be grounded to meet electrical code standards? Also I noticed that the Elk supplied panels all come with a green safety ground nut.

That is grounding the box for safety ground not the panel ground for transients. The panel itself (Control Board) floats and at one time had an earth ground connection years ago. It was determined that not to ground it for transients provided better protection then grounding it.

 

[hagak]

That is grounding the box for safety ground not the panel ground for transients. The panel itself (Control Board) floats and at one time had an earth ground connection years ago. It was determined that not to ground it for transients provided better protection then grounding it.

Ok I thought you meant box == panel but you are referring to the actually M1G board not the box. Cause if you have a high voltage J-box attached to the metal box and do not attach a safety ground I could see the potential for a very nasty shock should your wiring in the j-box short to the case.

 

[Del91574]

The enclosure is bonded to ground however the panel/circuit board is not grounded to EG.