Machine & Electrical Safety
Functional safety, safety devices, and electrical safety — explained from the controls bench.
Safety is engineered, not bolted on. This hub gathers the functional-safety standards (SIL, Performance Level, ISO 13849), the devices that implement them, and the electrical-safety side — NFPA 70E and arc flash — all from the perspective of the engineer wiring the panel and writing the logic.
Functional Safety & Standards
Functional Safety Basics
The safe state, the lifecycle, IEC 61508/61511, and what changes in your PLC.
What Is SIL?
SIL 1-4 explained, PFD, and how it maps to your safety PLC.
Performance Level (ISO 13849)
PLa-PLe, the risk graph, MTTFd, DC, and Category.
SIL vs Performance Level
IEC 62061 vs ISO 13849 and how PL maps to SIL.
Safety Circuit Categories
Category B, 1, 2, 3, 4 and how they relate to PL.
Functional vs Process Safety
How they differ, relate, and where the safety PLC fits.
Safety Devices & Circuits
What Is a Safety Relay?
Dual-channel monitoring, reset types, and E-stop wiring.
How a Light Curtain Works
Resolution, safety distance, muting, and OSSD wiring.
Safety Laser Scanner
Protective and warning fields, and AGV use.
Machine Guarding Explained
Guard types, safeguarding devices, and the hierarchy of controls.
Emergency Stop Categories
Stop Category 0, 1, and 2 per IEC 60204-1.
Two-Hand Control
Types, synchronous actuation, and anti-tie-down.
Lockout/Tagout Procedure
The six OSHA steps and hazardous energy types.
Electrical Safety & Arc Flash
What Is NFPA 70E?
Electrical safety in the workplace and energized-work rules.
What Is Arc Flash?
Causes, hazards, boundary, and PPE.
Arc Flash Boundary
The 1.2 cal/cm2 distance and how it is determined.
Arc Flash PPE Categories
CAT 1-4, cal/cm2 ratings, and ATPV.
Incident Energy Explained
What drives cal/cm2 and how to reduce it.
Arc Flash vs Arc Blast
The thermal hazard vs the pressure hazard.
NFPA 70E vs OSHA
Law vs consensus standard, and why you follow both.