Electrical test
PCB (askarel) content in oil
Testing transformer oil for polychlorinated biphenyls (PCB / askarel) — a regulatory and environmental compliance requirement before servicing or disposal.
Testing for polychlorinated biphenyls (PCB, historically sold as askarel) determines whether a transformer's oil is contaminated with these regulated, toxic compounds. It is a compliance prerequisite: contaminated oil cannot be serviced, transported or disposed of like ordinary oil, and cross-contamination must be ruled out before any intervention.
Askarel was used for decades as a fire-resistant dielectric fluid before PCBs were identified as toxic and environmentally persistent and were banned or strictly regulated. Older transformers may still contain PCBs, and — just as important — mineral-oil units can be cross-contaminated above regulatory thresholds through shared handling equipment. The only way to know is to test.
The analysis quantifies PCB concentration in the oil, in ppm, against the regulatory limits that define how the oil and equipment must be handled. The result determines the legal and safety obligations: labeling, controlled handling, transport and disposal by authorized parties, and whether the unit can be serviced at all without special precautions.
At TEVKO the PCB content is determined in an accredited laboratory and interpreted against the Mexican environmental regulation NOM-133-SEMARNAT and methods such as IEC 61619. The result is documented in a protocol so the owner has the compliance evidence needed for service, decommissioning or disposal decisions — handled correctly, not assumed.
When PCB testing is needed
Compliance before service/disposal
Confirms whether oil and equipment must be handled as PCB-regulated before any intervention or disposal.
When it applies: Decommissioning, disposal, or servicing older units.
Cross-contamination check
Verifies a mineral-oil unit has not been contaminated above thresholds through shared handling equipment.
When it applies: Audits and acquisitions of used transformers.
How we run the test
Sampling
Oil sample taken under controlled procedure to avoid cross-contamination.
Laboratory analysis
PCB concentration quantified in ppm in an accredited laboratory.
Compliance interpretation
Compared against NOM-133-SEMARNAT limits to define handling obligations.
Protocol
Documented report serving as compliance evidence for service or disposal decisions.
Frequently asked questions — pcb (askarel) content in oil
Why test a transformer's oil for PCBs (askarel)?
Because PCBs are toxic, environmentally persistent and strictly regulated. Older units may contain askarel, and mineral-oil units can be cross-contaminated through shared equipment. Testing is required before the oil or equipment can be serviced, transported or disposed of.
What happens if the oil contains PCBs above the limit?
It triggers regulatory obligations: controlled labeling, handling, transport and disposal by authorized parties, per the applicable environmental regulation. Contaminated oil cannot be treated or disposed of like ordinary oil.
Can a mineral-oil transformer be contaminated with PCBs?
Yes. Cross-contamination through shared filtering, sampling or filling equipment can raise PCB levels above regulatory thresholds even in a unit that originally used mineral oil — which is why testing is the only reliable way to know.
What standards apply to PCB testing in Mexico?
Handling and disposal follow the environmental regulation NOM-133-SEMARNAT, and the laboratory determination uses methods such as IEC 61619. TEVKO documents the result as compliance evidence for service or disposal decisions.
PCB (askarel) content in oil in images
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