Machine safety: Does effective grounding include ancillary hand rails, fences, and more?

How inclusive is effective grounding for machine safety? Should safe machine grounding consider hand rails, walkways, and protective fencing?


How all encompassing is effective grounding for machine safety? Does this requirement really include things like hand rails, walkways and protective fencing?


The discussion regarding effective grounding is really broad and sometimes vague in my opinion. Certainly it’s intended to protect people from being electrically shocked and to guard against any false or unintended operation or movement of a machine. Some standards will have pages of requirements whereas other standards might have one paragraph “referencing” a manufacturer’s specifications. Most of these standards benefit by some level of interpretation by a knowledgeable person for the most effective grounding applications. Let’s look at one general description/requirement from NFPA 79; 2012: Equipment Grounding. The machine and all exposed, non-current-carrying conductive parts, material, and equipment likely to be energized shall be effectively grounded. Where electrical devices are mounted on metal mounting panels that are located within nonmetallic enclosures, the metal mounting panels shall be effectively grounded. Where specified by the manufacturer, components and subassemblies shall be bonded to the equipment grounding (protective bonding) circuit in accordance with the manufacturer’s instructions.


The first sentence of this standard can easily be interpreted as though provisions like hand rails, walkways, and protective fencing probably don’t need grounding or bonding provisions.


However, if the walkway or hand rail connects a machine to another machine which also has an electrical control system and devices, industry experts have often recommended that these metallic non-current-carrying conductive parts be effectively grounded.


Does anybody know why?


J.B. Titus, CFSE

Has this presented you with any new perspectives? Add your comments or thoughts to the discussion by submitting your ideas, experiences, and challenges in the comments section below.


Related articles:

NFPA 79; 2012 – Electrical Standard for Industrial Machinery

ANSI B11.19 – 2012 Performance Criteria for Safeguarding

IEC 60204-1: 2005 Safety of machinery – Electrical equipment of machines

Contact: for “Solutions for Machine Safety”.

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.