Professionalism and TrustMy Account Apply for Membership My Account Apply for Membership National Association of Infrared Specialists 16192 Coastal Highway, Lewes, Delaware 19958 NAIS Electrical Systems Standards of Practice (ElecSOP) This standard sets the requirements for infrared surveys of electrical power systems and distribution equipment. Section 1: Purpose, Scope and Alignment 1.1 Purpose. To set a uniform, defensible minimum standard for infrared surveys of electrical equipment. 1.2 Alignment with NAIS Core Standards. This standard is an addendum to the NAIS Core Standards of Practice (CoreSOP) and the NAIS Code of Ethics. Everything in the CoreSOP applies unless this standard says otherwise. It relies on ASTM E1934 (examining electrical and mechanical equipment with infrared thermography), NFPA 70E (electrical safety in the workplace), NFPA 70B (electrical equipment maintenance) and NETA MTS (maintenance testing specifications). 1.3 Scope. Panels, breakers, switchgear, motor control centers, transformers, disconnects, bus duct, conductors and connections in power distribution systems. 1.4 Exclusions. This standard does not cover electrical testing, code compliance, engineering analysis, or repair. Photovoltaic arrays are covered by the Specialty Applications standard. Section 2: Safety Electrical surveys carry arc-flash and shock risk. The thermographer shall follow NFPA 70E and the site's electrical safety program, and wear the protective equipment the site's hazard assessment requires. Only a qualified person, as NFPA 70E defines that term, shall open or remove an enclosure cover. A thermographer who is not qualified shall not do so, and a qualified electrician should. The thermographer shall stay outside the approach boundaries and should use a telephoto lens where that makes it possible. The survey shall be stopped and the client told at once if an anomaly suggests imminent failure. An electrical survey shall be done only by a person trained in the electrical safety rules that apply to the site. Section 3: Load and Conditions Equipment shall be surveyed under normal operating load, ideally at least 40 percent of nominal design capacity, consistent with the load guidance in NETA MTS and ASTM E1934. A survey at a lower load shall be recorded as such, and its findings reported as possibly understated. The load at the time of the survey shall be recorded where it can be read, for example with a clamp meter or from the building system. Where it varies, record the highest value. Wind, direct sun and heat from nearby equipment shall be recorded because they affect surface temperature. Equipment should have run under steady load for at least 3 hours before the survey, or the report shall say it did not. Section 4: Procedure Image each connection, termination and device from the front and from other angles where reachable. Compare each with similar components under the same load, such as the other two phases. Record the absolute temperature of the hottest point, the reference temperature, and the delta-T between them. Where the surface is low-emissivity metal, follow CoreSOP Section 6.5. Insulated conductors should be read at the insulation, not at the bare metal. Report separately a hot spot with a visible cause, such as a loose lug, and one with no visible cause. Section 5: Severity Classification Severity is assessed from the delta-T over the reference, which is the adjacent similar phase under equal load or, where there is none, ambient. Each finding shall also record its absolute temperature, the load and the component's temperature rating. Class Delta-T over reference Meaning Recommended action I, Minor 1 degrees C to under 11 degrees C (1.8 degrees F to under 20 degrees F) Possible deficiency Monitor and repair during routine maintenance II, Intermediate 11 degrees C to 30 degrees C (20 degrees F to 54 degrees F) Probable deficiency Repair at the next scheduled outage III, Serious Over 30 degrees C (over 54 degrees F) Major discrepancy Take immediate corrective action A finding shall be placed in a higher class, regardless of delta-T, when the absolute temperature is above the rated limit of the component or its insulation, or when the load is well below normal. A finding that depends on a reading the thermographer could not verify shall be reported as "unverified." Section 6: Follow-up The report shall recommend that a qualified electrician investigate each finding, in order of class. After repair, the thermographer should recheck the component under similar load and record the result. Section 7: Reporting The report shall meet CoreSOP Section 7, with the following added: the load at the time of the survey, the class of each finding, the component's rated temperature, and the location of each component by panel or equipment identifier. Section 8: Limitations This survey shows surface temperature only, and enclosures, covers and shields hide components. A cool reading does not prove that a connection is sound, and a survey at low load can understate a fault. The CoreSOP limitations statement shall appear in every report.

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