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Grounding & Bonding Applications Handbook  

Get your FREE copy of the Newson Gale 's Grounding and Bonding Applications Handbook. The Handbook is a practical guide for engineers and plant managers who need to control the hazards associated with uncontrolled discharges of static electricity within flammable and explosive atmospheres.

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Grounding and Bonding Applications Handbook

Why are FM approved grounding clamps important for static grounding protection?

Grounding and bonding is the primary means of ensuring HAZLOC equipment cannot get charged by static electricity. This ensures the ignition of flammable atmospheres is prevented.  NFPA 77 “Recommended Practice on Static Electricity” states that the resistance of any static grounding or bonding circuit should not have an electrical resistance of more than 10 ohms between the grounded object and a True Earth grounding point. Things that can prevent a grounding clamp achieving a 10 ohm connection are:
  • An inability to penetrate paint coatings, rust and product deposits.
  • An inability to maintain good electrical contact with vibrating equipment.
  • Clamp designs that can be accidentally displaced from the equipment requiring static grounding protection.

Factory Mutual approved clamps are tested to ensure they meet the performance criteria that an effective static grounding clamp should be capable of delivering. These tests are: 
  1. Electrical continuity testing - ensures the total resistance through the clamp from the teeth to the cable connection point is 1 ohm or less.
  2. Vibration frequency testing – tests the clamp’s ability to maintain good electrical contact with vibrating equipment through a range of different vibration frequencies.
  3. Clamp force testing - ensures the grounding clamp meets the minimum clamping pressure required.
  4. Mechanical strength testing - ensures the clamp cannot be easily loosened or easily pulled from from the equipment requiring static grounding protection.

What are the benefits of using tungsten carbide teeth? 

Tungsten carbide is one of the hardest materials in use in industry today and when used in combination with a well designed clamp spring, has the capability to continuously bite through coatings, rust or product deposits that a basic alligator clip or welding clamp would struggle with. Sharpened tungsten carbide teeth are a standard feature of Newson Gale's heavy duty clamps.


Tungsten carbide teeth penetrate connection 
inhibitors like paint coatings and rust.

Why is spring design so important?

A grounding clamp's effectiveness at protecting against the ignition of flammable atmospheres should not be judged by how difficult it is to open the clamp handles - that is the result of a poorly designed spring and clamp assembly. A well designed spring and clamp assembly should enable an operator to apply a reasonable amount of torque to open the clamp without causing stress to their hand.

The most important thing to know is what pressure is applied at the business end, i.e. where the clamp teeth are trying to make a solid electrical connection to the equipment at risk of static charging. The combination of spring material, spring diameter, the number of active spring coils and the length of the spring legs have all been factored into Newson Gale grounding clamps to balance operator ergonomics with a clamping force that can match and exceed the testing requirements of Factory Mutual.  

 

 

Newson Gale springs are designed and analyzed with the aid of Finite Element Analysis technologies.

What is the difference between bonding and grounding?

The act of grounding an object is to ensure the object is at zero volts (0 V) potential, i.e. ground potential. The intention is to ensure no electrostatic charges can build up on the equipment, that would result in a voltage being present on the object, leading to an eventual discharge of a static spark. This can only be achieved by connecting that object to a True Earth grounding point.

A True Earth ground is a grounding point that has been tested and proven to be connected to the "general mass" of the Earth. Any object connected to the mass of the Earth will not accumulate electrostatic charges, therefore there is no spark ignition risk when the process or operation is under way. This object is "grounded".

Bonding is the act of connecting objects together to ensure they are at the same voltage. Bonding distributes electrostatic charge equally between the bonded objects, so that there is no risk of sparking between the objects. Bonding does not remove the risk of static sparks entirely. If an object at a lower voltage, e.g. a grounded hose, comes into contact with the equipment, this could result in a static spark discharge. The best way of eliminating this risk is to bond the objects together and connect one of the bonded objects to a verified True Earth grounding point.

What is Cen-Stat™ cable?

Cen-Stat™ is a coating and conductor formula based on 30 years’ experience of the rigorous demands of industrial work environments. It combines the features of a well-respected DuPont plastic that provides a wide operating temperature range, resistance to a wide range of chemical products and enhanced mechanical durability. Included in the formulation is static dissipative material that prevents the cable from carrying an electrostatic charge and additives that provide protection against exposure to ultra-violet light. The conductor is composed of multi-stranded galvanized steel threads that provides a conductor cross-sectional area of 11 AWG (4 mm sq.), and with the coating included provides a cable diameter of 0.25” (6 mm). Cen-Stat is supplied in retractable spiral lengths of 10 ft. (3 m), 16 ft. (5 m), and 32 ft. (10 m). Cen-Stat is supplied with Newson Gale's X45 and X90 heavy duty clamps.

Cen-Stat grounding and bonding cable

What is Cab-Lite cable?

Cab-Lite is a 1/8" multi-stranded galvanized steel conductor protected by a hi-vis yellow coating and is supplied with the PIRANHA clamp in 5 ft., 10 ft. and 20 ft. lengths on the R20, R50 and R75 reels.

PIRANHA grounding clamp