What should I do if my insulation resistance is sub normal?
If the one-minute insulation resistance value is subnormal, or if the 60 second/30 second insulation resistance ratio is no greater than one at this point then a drying operation may be desirable before using a higher test voltage.
What do maintenance practice trends indicate about the value of insulation?
Maintenance practice trends indicate the value of testing insulation with dC voltages at levels somewhat higher than the peak value of the rated AC voltage of the equipment being tested.
Do I need to test the insulation in my plant?
If the apparatus you are testing has very small capacitance, such as a short run of house wiring, the spot reading test is all that is necessary. However, most equipment is capacitive and so your very first spot reading on equipment in your plant, with no prior tests, can be only a rough guide as to how good or bad the insulation is.
How do I start insulation testing?
To start insulation testing there is one general rule: put first things first. That is, review all the electrical equipment and classify it as to relative importance.
How to start insulation testing?
To start insulation testing there is one general rule: put first things first. That is, review all the electrical equipment and classify it as to relative importance. For example, if that AC motor failed in department A, how would it affect overall plant production? your production people can certainly help in this and should be vitally interested in the idea.
What are the variables that affect the insulation resistance of electrical equipment?
Insulation resistance of electrical equipment is affected by many variables such as the equipment design; the type of insulating material used, including binders and impregnating compounds; the thickness of the insulation and its area; cleanliness, moisture and temperature. For insulation resistance readings to be a conclusive measure of the condition of the equipment being tested, these variables must be taken into consideration.
How much insulation should an oil breaker bushing have?
In the case of outdoor oil circuit breaker bushings, experience has shown that any bushing, with its assembled associated insulating members, should, for reliable operation, have an insulation resistance value above 10,000 megohms at 20°C. This assumes that the oil within the tank is in good condition, that the breaker is separated from its external connections to other equipment, and that the porcelain weather shield is guarded. This means that each component such as the stripped bushing itself, cross-member, lift rod, lower arcing shield, etc., should have an insulation resistance in excess of that value.
Is Megger insulation flammable?
So far as is known, there is no fire hazard in the normal use of a Megger insulation tester. There is, however, a hazard when testing equipment located in inflammable or explosive atmospheres.
Does humidity affect insulation?
you might expect, therefore, that increasing humidity (moisture content) in the surrounding (ambient) air could affect insulation resistance. And it can to varying degrees.
Do insulation testers need voltage scales?
Some insulation testers may be supplied with a voltage scale to check for the absence of voltage before insulation testing . As explained in the Safety Precautions section, however, insulation testers should never be connected to energized lines or equipment when operated in any of the Insulation Test or Resistance Test modes.
Occupational Exposure Before 1982
Insulation Workers Encounter Asbestos
- When insulators handle, install, or remove asbestos products (or contaminated vermiculite), there’s a significant chance the mineral’s spindly fibers will become airborne. Once airborne, workers and nearby residents can easily inhale or ingest them. Once the fibers are lodged in the throat or other nearby areas in the body, they’ll damage tissues until after so many years of dam…
Laws and Regulations Against Asbestos
- Once asbestos was classified as a carcinogen (i.e., cancer-causing agent), all handling of it became heavily regulated. Government organizations put several laws in place to regulate the use and enforce proper removal of the mineral. Building owners and managers are held responsible for removing asbestos from contaminated structuresbefore allowing people to work or reside th…
Think You’Ve Been Exposed to Asbestos?
- If you or a loved onehas worked in the insulation industry and fear for asbestos exposure, visit your doctor immediately. Especially if you exhibit any symptoms of lung illness such as chronic coughing, chest pain, or recurrent sore throat. Your doctor will test you for the most likely cause first. Based on the results, they’ll move on for more tes...