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Putting Your Electrical System Into Perspective
Tip provided by Brady Infrared Inspections, Inc.

Infrared inspections of electrical systems can help to improve the efficiency of a preventive maintenance program. In this Tip, we focus on several key considerations for setting up inspection routes.

Electrical infrared inspections are best performed when carefully designed routes are set up listing the equipment to be inspected. But how does one go about designating a route? To answer this, you must first understand your electrical system layout. Keep in mind that electrical systems are designed to fit the type of operation of a facility. In general, in-plant electrical systems begin with higher voltage classes nearest the incoming source of electricity and branch down to lower voltage classes via transformers to meet specific power demands throughout the facility.

As a general guideline, the following is a list of the types of electrical systems found at various facilities:

Industrial / Large Manufacturing

• 23 to 13kV supply voltage on site that is stepped-down to 4160V and 277/480V for various motor and lighting loads (substations, load interrupter switches and large transformers are common with this set-up)
• 277/480V is stepped-down to 120/208V via transformers for receptacle, computer, and lighting loads

Medium to Small Manufacturing / Large Commercial / Healthcare

• 277/480V supply voltage is brought into the facility via outside pad-mount or pole-mounted transformers to be used for various motor and lighting loads and stepped-down to 120/208V via transformers for receptacle, computer, and lighting loads

Small Commercial / Office

• 120/208V or 110/240V supply voltage brought into the facility via outside pad-mount or pole-mounted transformers used for receptacle, computer, and lighting loads

Infrared inspection routes can set up based upon various criteria including but not limited to, specific areas or operations in your facility, by voltage class of equipment, by individual circuit branches, by criticality to operation of a facility, or other determining factors deemed important.

Keep in mind that routes should be limited to the amount of equipment that can inspected in a single day or shift. Routes should also start with high-voltage equipment closest to the incoming power source as failures high in the electrical hierarchy generally affect larger portions of the facility than lower voltage equipment.

~ Tip provided by Brady Infrared Inspections, Inc.

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