Equipotentiality (line on an upside-down triangle)

The standard’s wording, as the sources below reproduce it:

“To identify the terminals which, when connected together, bring the various parts of an equipment or of a system to the same potential, not necessarily being the earth (ground) potential, e.g. for local bonding.”

IEC 60417-5021 · IEC 60601-1, Table D.1, symbol 8

What it means for you

It marks a small stud or pin on the back of the device for a bonding cable (usually green and yellow). In hospital rooms and operating theatres, the equipment around a patient is wired to the same bonding bar so that no two metal parts can sit at different voltages. Mindray’s manual gives the reason: connect the equipotential terminals of devices used together “to eliminate the potential differences between them”. At home the stud is normally left unused.

Whether a device is right for you is a question for your pharmacist, nurse or doctor.

What it looks like: A short vertical line coming down onto the flat top of a triangle that points downwards, drawn in outline — sometimes with a small v inside it.
Where you see it: On the rear panel of patient monitors, anaesthesia machines, infusion-pump racks, dialysis machines and other mains-powered hospital equipment, next to the power inlet.
Other names: equipotential terminal; potential equalization; bonding terminal; POAG terminal

What it does not tell you

It is not the protective-earth terminal (earth sign in a circle) and does not make the device earthed: the mains plug does that. It does not say the device is safe to use without it, or that it needs it — that is for the installer and the instructions.

More symbols in “Marks on the device casing”

Non-ionizing electromagnetic radiation (radio mast with waves)IEC 60417-5140 Electrostatic sensitive devices (crossed hand in a triangle)IEC 60417-5134 Protective earth (earth in a circle)IEC 60417-5019Explained on its own page →Class II equipment (double square)IEC 60417-5172Explained on its own page →Stand-by (broken circle with a line)IEC 60417-5009Explained on its own page →Dangerous voltage (lightning arrow) and the yellow “warning, electricity” signIEC 60417-5036Explained on its own page →Alternating current (sine wave)IEC 60417-5032Explained on its own page →“ON”/“OFF” push-push (line inside a circle)IEC 60417-5010Explained on its own page →

Sources

IEC 60417 and IEC 60601-1 are paid standards, so the wording above is quoted as 4 publishers’ public documents reproduce it; our drawing is not the IEC artwork. Each was fetched and read on the date shown:

Boston Scientific: Symbols Glossary — Row IEC 60417-5021 “Equipotentiality”, IEC 60601-1 Table D.1, Symbol 8: “To identify the terminals which, when connected together, bring the various parts of an equipment or of a system to the same potential, not necessarily being the earth (ground) potential, e.g. for local bonding.” Checked 2026-09-28.
Hillrom: Symbols Glossary (80022945 Ver. J) — Row “Equipotentiality”, IEC 60417-5021, same wording with “(e.g., for local bonding)”. Checked 2026-09-28.
ICU Medical: Symbols Glossary (IFU0000017 Rev 02) — Row “Equipotential Terminal (Ground) — Identifies terminals for equipotential (ground)”, IEC 60417 reference # 5021. Checked 2026-09-28.
Mindray: iPM 12/iPM 10/iPM 8/iPM 7/iPM 6/iPM 5 Patient Monitor Operator’s Manual — Section 1.2 “Equipment Symbols” shows it as “Equipotentiality”; the rear-panel description says to connect the equipotential grounding terminals of devices used together “to eliminate the potential differences between them”. Checked 2026-09-28.

Plain-language parts are in our own words; quotations are the sources’ wording.