Is a non grounded surge protector a fire hazard?

[jmblack6307_apc]

This was originally posted on APC forums on 3/27/2013

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Will a surge protector plugged into an outlet that is not grounded or grounded improperly, cause a fire hazard or just fail to provide surge protection?

My receptacle tester as well as the surge protector ground fault both indicate it's not properly grounded or not at all.  I am only using the surge protector for the extra sockets to plug items into and realize there is no surge protection to it.

Just want to make sure I am not creating a fire hazard.  Everything seems to be ok, and we have been here in this old NYC apartment building 5 years not, but I always like to error on the side of caution.  Eventually, I believe the landlord will rewire, but in the meantime I want to be safe. 

[BillP · Accepted solution]

This reply was originally posted by Angela on APC forums on 3/27/2013

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I have a few ungrounded outlines in my home as well.

Anyway, I imagine your site wiring fault LED is lit on your UPS? We have some documented information here on that in the knowledge base - FAQ and search for article ID FA158817. Here is an excerpt.

If the outlet that the APC UPS unit is plugged into is not properly grounded or properly wired, the unit will attempt to absorb the excess voltage instead of redirecting it to ground. It would be like attempting to catch a bullet with a catcher mit, where as if the light is not on it would be able to redirect the excess voltage to ground. Therefore, in order to maintain your warranty and protection under APC's Equipment Protection Policy, be sure that the APC unit is only plugged into a properly grounded outlet where the Site Wiring Fault Indicator (SWFI) light is not illuminated.

If this condition exists and a surge comes through, the unit would "fail open" and sacrifice itself to absorb that surge rather than damaging your equipment. I imagine if the surge was so long and so large, there is a risk that the unit could burn up itself because of that surge and the inability to shunt it to the ground.