Hanger static ground receptacle testing

[Brand New]

I was asked to perform a test on the static grounding receptacles in a hanger on an army base. They are going to replace the receptacles and want me to test before and after to make sure they are at least equal to exitsing.
I called the maintenance contractor that does the annual testing to get the procedure they use and the only info they would give me is that they use a megger and test to building steel. I have spent hours on the internet trying to come up with a standard testing procedure and have come up with zip about using a megger. I did a few with an ohm meter and came up with readings between 10k and 30K ohms and with the megger on 500V get 0 ohms.
The test reports from the maintenance company all just say less thea 1K ohms.
Any suggestions or advice would be greatly appreciated.

 

[kwired]

Are you talking about a grounding system designed to connect to equipment to discharge static electricity - like possibly for working on solid state equipment that may be sensitive to static charges?

If so megger is not what you want, higher the voltage applied the more easy it is to push current. You want something that will discharge static even at low voltage levels so I would think testing should involve application of low voltages.

How to get desired test results for specifically what you are looking for I really don't know.

 

[Brand New]

I am not sure if it is for the working on electronics aspect or the static igniting fuel. Not much info out there on it.

 

[kwired]

I am not sure if it is for the working on electronics aspect or the static igniting fuel. Not much info out there on it.

If it is for prevention of static igniting fuel I would say check into fuel codes more so than electrical codes. Most of what may be related to fuel in NEC is going to be Art 500 - 516 but those don't really apply much to discharge of static as they do to prevention of ignition by electrical equipment.

 

[masterinbama]

Checking to building steel or any other conductive material is all that is required.

All the static lines do is insure that no spark occurs when the fueling nozzle contacts the aircraft.

 

[kwired]

Checking to building steel or any other conductive material is all that is required.

All the static lines do is insure that no spark occurs when the fueling nozzle contacts the aircraft.

Is fueling normally done inside the hangers? My first guess is it is never done there. Fuel may be present at times in a major repair area but not a storage hanger and even if general maintenance is done in the storage hanger.

 

[Brand New]

If I just need to check to building steel do I just use an ohm meter or a megger. If a megger what voltage?

 

[kwired]

If I just need to check to building steel do I just use an ohm meter or a megger. If a megger what voltage?

I think you need a meter that is accurate at very low resistance. The high voltage of a megger is not what you need as it is intended to measure very high resistances more accurately by applying more test voltage that a regular multipuropose meter just doesn't do.

 

[don_resqcapt19]

NFPA 77 for Static Control specifies that the bonding paths have a resistance of 10 ohms of less. I think that is just a number they picked for testing purposes. The IEEE Green Book says that a resistance of 1,000,000 or less will prevent static build-up.

 

[kwired]

NFPA 77 for Static Control specifies that the bonding paths have a resistance of 10 ohms of less. I think that is just a number they picked for testing purposes. The IEEE Green Book says that a resistance of 1,000,000 or less will prevent static build-up.

If that is the standard then fairly inexpensive multimeter should be accurate enough.

 

[sgunsel]

NFPA 77 is the Recommended Practice for Static electricity. NFPA 77 specifies a maximum resistance of 1 megohm (1,000,000 ohms) to prevent static sparks for bonding and grounding. In practice, higher resistances, up to 100 megohms may suffice. It only mentions 10 ohms as a guideline where metallic conductors are used to indicate if conductors and connections may be deteriorating. A 500 volt megohm meter is the preferred instrument for electrostatic resistance measurements since it will produce real world resistance measurements as applicable to the hazard. Below 500 volts, there is generally no hazard of an incendive discharge from static electricity.