HOSPITAL GROUND LOOP SIMULATOR
ELECTRICAL SAFETY · PATIENT PROTECTION · BIOMEDICAL ENGINEERING
⚡ SAFETY SIMULATION
▸ HOSPITAL ROOM — TOP-DOWN SCHEMATIC VIEW
Patient Type
Patient type determines body resistance and shock susceptibility.
Device Outlet Assignment
Live Measurements
0.0
Max ΔV (mV)
0.00
I through pt (μA)
1000
R patient (Ω)
0
Active Loops
DANGER LEVEL SAFE
SAFEWARNDANGERFATAL
✓ No ground loops detected. All devices share equal ground potential.
Wall Outlet Ground Potentials
▸ EQUIVALENT GROUND LOOP CIRCUIT — WORST-CASE PAIR
▸ REFERENCE — ELECTRICAL SAFETY IN CLINICAL ENVIRONMENTS (IEC 60601-1)

What is a Ground Loop?

A ground loop forms when two devices connected to the same patient have different chassis ground potentials (ΔV ≠ 0). The patient's body becomes part of the return current path between the two grounds.

Microshock vs Macroshock

Macroshock: Current via skin. VF threshold ≈ 100 mA. Perceptible at 1 mA.
Microshock: Current directly to heart (catheter). VF possible at 10–50 μA — undetectable by the patient!

When is it Dangerous?

With a cardiac catheter (R≈50Ω), just 0.5 mV ground difference induces 10 μA — enough for ventricular fibrillation. Saline IV lines provide a low-resistance path even without a catheter.

Prevention Strategies

• Use isolated power systems (IT) in ORs & ICUs
• All devices on the same outlet bus
• Equipotential bonding buses
• Avoid non-medical extension cords
• Regular ground continuity testing