bounding and grounding 2

[grandmanitou]

I recently got a new job in a plant that do repackaging and plastic grinding. Everything here is pretty old, and almost nothing nothing is grounded! An other problem I have with this is that the building is made of wood, so I cannot ground the machines to the structure.

Now, I need to resolve this but I never done that before. Shouldn’t be too complicated, but I was wondering if you guys have any tips regarding this.

The equipments being used: pneumatic conveyor, discs mill, plastic bin, sifter...

 

[SlideRuleEra]

In electric generating stations, where stray currents are likely, dedicated grounding systems are used. The typical arrangement is to encircle each building with a buried heavy copper cable that includes two or more ground rods. This is a closed loop, so that one discontinuity does not break the circuit. Equipment and even the (steel) building frames are connected to this grounding loop. An electrical engineer's input could be cost-effective, since oversizing copper cables/ground rods is expensive and the system conductivity should be tested.

http://www.SlideRuleEra.net

 

[boo1]

"The first step in any grounding design is to obtain accurate soil resistivity data. Second, it is necessary to determine which grounding configuration will give a specific resistance within the installation area. This can be determined by using formulas (IEEE Standard 142, Green Book) or nomographs for calculating the resistance of a single vertical rod. If the target earth-ground resistance is not achieved, it is necessary to use multiple rods, or another arrangement."

Another recommendation is that you contact a firm specializing in grounding system design. Grounding is a scientific process and one on which equipment protection and human safety are critically reliant. Define exactly what grounding installations and improvements will work best for your site. This eliminates trial and error, and reduces the overall cost of the grounding system by designing only what is needed to meet your specifications.

The most common is Single Vertical Rod Design. I have installed many of these systems using a grid approach, attaching the equipment to the grid with CLAD welds.

The earth-ground resistance for a single electrode, such as a driven rod or electrolytic rod, can be calculated from the following formula:
R = r/2 p(l(2l/r)(1 + 2K))
Where
R = Resistance (ohms)
r = Mean soil resistivity (ohm-cm)
l = Length of rod (cm)
r = Radius of rod (cm)
K = Coefficient

 

[Tobalcane]

grandmanitou

Well first, does the equipment ground thru the third prong on the plug and if so, is the receptacle on the wall grounded? If both are true then your machines are grounded

Just a quick observation…

Good luck


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Tobalcane