Friday, April 23, 2010

STOP! In the name of love (of keeping your body parts intact)

I don't know about you, but when it comes to power tools, they can be a bit scary when you realize that they can grab your cloths, hair, or the part you are working on and tear them-up in a fraction of a second.  Drill presses, router tables, planners, and table saws are some of the most powerful tools in your shop, so having a shut-off switch that is extremely visible and easy to slam a hand or knee onto is a really good idea.

Grizzly Power Tools ( makes the H8243 mondo power switch for this application.  For the price of a good pizza this dual voltage, single-phase Paddle Switch is rated for 110 Volt, 2 HP motors up to 35 amps, and 220 Volt, 3 HP motors up to 20 amps. The large paddle makes this switch ideal for emergency shut-offs.  It fits a standard single-gang electrical box, so you can mount it just about anywhere.

ANSI Standard 535.1 requires that the RED switch be mounted on a yellow background for maximum visibility, so slap a coat of yellow down before you mount that switch.

Do I have to have this?

According to most international machinery safety standards you probably should.  Here is a listing of relevant requirements for E-stops:
  • 98/37/EC The Machinery Directive - Clause 1.2.4 in annex 4 gives requirements for the emergency stop function for new machines. See also clause 1.2.2 Control devices (chapter “Standard and Regulations”).

    Council Directive 89/655/EEC of November 30, 1989 concerning the minimum safety and health requirements for the use of work equipment by workers at work, Clause 2.4 gives the requirements for the emergency stop function for older machines. See also clause 2.1 (chapter “Standard and Regulations”).
  • EN ISO 13850 Safety of Machinery - Emergency stop—Principles for design.  A harmonized standard that gives technical specifications for the requirements on the Machinery Directive.  Can also be used for older machinery.
  • EN 60204-1 Safety of Machinery - Electrical equipment of machines —Part 1: General requirements.  This is a harmonized standard that gives requirements for the electrical equipment of machinery including the emergency stop actuator/function. See clauses 9.2.2 and
  • OSHA publication "Safeguarding Equipment and Protecting Employees from Amputation" can be downloaded here:

For industrial safety switch systems that meet a much higher level of performance, you need to look toward systems that are engineered solutions that utilize specialized sensors, switches, relays, and annunciators.  While the Grizzly paddle switch is a huge step in the right direction, there is still much more you can do to safeguard your shop workers.

Also see: 

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