When you modify an electrical system, electrical power studies are necessary. But, have you ever stopped to ask why? In short, a steady, reliable, and well-maintained electricity supply is imperative to the success of any business. So, even minor electrical problems or faults can have crippling effects on a company. Furthermore, extended outages can result in significant downtime, equipment damage, and expenses associated with finding and repairing damaged equipment.
Therefore, any changes to the electrical system can impact the fault calculations and settings. Electrical power studies ensure that electrical systems operate at optimal power and that clearing fault currents is done safely and timely. But, what do you need to do to prepare for electrical power study?
10 Ways to Prepare for Electrical Power Studies
1. Identify Utility main point of entry (MPOE) fault contribution Ampere Interrupting Capacity (AIC) value
First, begin by identifying which utility supplies power to the building site. In order to conduct power studies, you need to have the available fault current rating from the utility that feeds the building(s). So, you need to request this information from the utility engineering department. But, be sure to have the building address and electrical meter serial number handy, as the utility will need these to identify the available fault current rating.
2. Up to date electrical one-line diagram(s)
In short, a one-line diagram of an electrical system is a blueprint for the electrical system. It depicts the power distribution path from the incoming source to each downstream load. Typically, one-line diagrams must include the equipment rating and size and the circuit conductors and protective devices.
3. Identification of all electrical feeders with conduit type, wire type, and length of wire
Unfortunately, one-line diagrams may not always depict electrical feeders’ point-to-point paths. In this case, you will need to conduct an on-site review to locate these paths. In addition, on-site reviews are crucial to determine the length and type of conductor(s) and conduit type needed for the electrical study.
4. Identification of electrical distribution equipment
An on-site review is necessary to verify the accuracy of the electrical equipment and gear specification on the one-line diagram. Conducting an on-site review confirms brand, type, size and rating.
5. List and identify all electrical transformers
Creating a list of all the electrical transformers is essential when preparing for electrical studies. The list must identify each electrical transformer by type, size, rating and impedance.
6. Identify all overcurrent protection devices installed in the electrical system
To properly conduct electrical studies, you must first identify all overcurrent protection devices installed on the electrical system. Identifying overcurrent devices in electrical gear and electrical equipment should include the brand, type, voltage and AIC ratings.
7. Determine the LSIG settings or fuse type and ratings of all overcurrent devices
Each overcurrent device must have LSIG settings (long time, short time, instantaneous, ground) defined in the as-found conditions of each device. However, fusing installation requires the identification of the fuse ampacity, type and AIC ratings.
8. Up to date electrical panel schedules
Electrical panel schedules need to indicate breakers sizes and label load types to identify all equipment loads with motor loads. Electrical studies must include motor loads, as well as the feeder size, conduit size and the length of wire.
9. Equipment list identifying electrical motors
Electrical studies require the identification of all equipment with motor loads. Therefore, the equipment list must identify all motor loads type, size and horsepower rating.
10. Update building floorplans
Last but certainly not least, you need to update building floorplans for upcoming electrical power studies. Therefore, the floorplans must specify the locations of:
- Electrical equipment, distribution gear, and panels
- Mechanical/air conditioning units
- Motor loads
APT 4 Solutions
Energy is at the forefront of many Americans minds right now. As a result of the fast evolving situation between Russia and Ukraine many countries are reevaluating how and where they procure energy. However, we also must look at how to optimize the energy we already have. Keeping your facility’s power equipment healthy is essential. Unfortunately, this is becoming increasingly difficult due to advancing technologies, energy codes, poor power quality, and high energy costs. So, why try to navigate it alone?
APT delivers a turnkey solution. We work with clients looking for ways to reduce the risk of electrical failures. At APT, we take power equipment to the next level, providing engineering, installation, startup, and maintenance services. Above all, our team will design the right solution to fit your facility’s needs.
Looking for more information?
Contact an APT professional today. Let’s work together to find the best solution for your facility.
Brian Curnutt | APT Field Service Manager