AAMI ES1: The Pass/Fail Values Behind Every Electrical Safety Inspection
ANSI/AAMI ES1-1993 (R2020) sets the leakage-current and ground-resistance limits every biomedical technician tests against. This is the reference sheet.
Overview
ES1 is the standard that answers a very specific question: how much leakage current is safe on line-powered patient-care equipment? The limits are tighter for equipment with direct cardiac connection (type CF) and looser for equipment that touches skin only (type B).
TJC, NFPA 99, and most state licensure frameworks defer to ES1 for the actual numeric pass/fail values. PBES documents every measurement against these limits so administrators have an unambiguous record.
Requirements checklist
What's actually required.
Ground-wire resistance ≤ 0.5 Ω
Measured from equipment chassis to the ground pin of the power cord.
Chassis leakage limits by patient contact type
Type B/BF: ≤ 100 µA normal polarity, ≤ 500 µA reverse polarity. Type CF (direct cardiac): ≤ 10 µA normal, ≤ 50 µA reverse.
Lead leakage on isolated patient leads
≤ 10 µA for type CF equipment (defibrillators, patient monitors with pressure-cath capability, some ECGs).
Test conditions documented
Line voltage, polarity, and neutral state recorded so the reading is reproducible.
Reference table
Values and limits.
| Equipment class | Ground resistance | Chassis leakage (normal) | Lead leakage |
|---|---|---|---|
| Type B (skin contact) | ≤ 0.5 Ω | ≤ 100 µA | N/A |
| Type BF (skin, isolated) | ≤ 0.5 Ω | ≤ 100 µA | ≤ 100 µA |
| Type CF (direct cardiac) | ≤ 0.5 Ω | ≤ 100 µA | ≤ 10 µA |
FAQ
Common questions.
Is AAMI ES1 the same as IEC 60601?
They're related but distinct. ES1 is the US-focused standard commonly used for periodic electrical safety inspections in the field. IEC 60601 is the international product-safety standard used mostly during design, type-testing, and manufacture.
How do I know which equipment is type CF versus type B?
The device's label carries a symbol — a heart in a box for CF, a person in a box for BF, and a person only for B. When it's unclear, PBES documents the tested classification on the service record.
How often should ES1 testing happen?
Annually is typical for patient-care equipment. Facilities may test more frequently based on device risk, incident history, or the facility's medical equipment management plan.
Related PBES services
Services that put this into practice.
Facility passed annual electrical safety inspection.
142 patient-care devices tested across 4 procedure rooms and 11 exam rooms. All findings catalogued with serial numbers, locations, and remediation status.
Illustrative sample — facility, technician, and device data shown are fictional.
Sample deliverable
See exactly what your surveyors will see.
Every PBES visit ends with a full Equipment Program Manual — device inventory, electrical safety results, PM status, and remediation notes, organized the way TJC, AHCA, and AAAHC surveyors read them. Request the full 47-page sample packet and we'll send it to your inbox.
- Executive summary + KPIs at a glance
- Per-device results with serials, locations, risk tier
- Photo-documented remediation and PM history
- Signed technician sign-off and inspection dates