Written by Susan Rice
The electrical systems within an industrial facility are rarely thought of until the lights, HVAC systems, motors, communications, and/or the powered process systems stop working.
The they are immediately thought of but unfortunately by then it’s too late.
The results of this electrical equipment failure can be:
- Production has been stopped and may be for quite some time due to availability of replacement equipment;
- An emergency condition may be caused from this situation including an: explosion, fire, injury or death;
- The cost of the repairs or replacement of the failed electrical equipment and/or impacted production equipment and system which cost much more in a reactive/emergency mode rather than a prescriptive/planned mode;
- The high cost of lost production downtime including labor, profits and loss of credibility to customers.
Electrical equipment and components have a life expectancy and will eventually fail like any other components in an industrial facility. Although occurring less often than mechanical failures due to less moving parts; it is essential to perform yearly assessments on electrical equipment as well.
Pearl Engineering’s electrical team have been hired to do such electrical equipment and component assessment studies for the following reasons:
- A client is interested in purchasing an existing industrial facility;
- A client is upgrading their process;
- Following an annual electrical assessment one of the electrical systems is not code compliant.
In this article we will be addressing “Purchasing an existing industrial facility scenario.” We will be providing case studies for the other two scenarios in future weeks.
EXISTING FACILITY PURCHASE CONSIDERATION
The following is an example of an electrical assessment and load study that we had done at a former industrial facility that has since been shut down and sold by the client.
A Cost Estimate and Photos are not included for proprietary concerns.
Objective
The objective of this project was to perform an Initial Site Assessment for a client who was interested in purchasing an existing plant to provide observations, recommendations, and cost estimates for code compliance.
Electrical Assessment Summary
Exterior
- The insulation on conductors that feed the Building from the East 1500 kVA Transformer are fraying and are in very poor condition.
- There is also an electrical enclosure in the same area on the Boiler Building that is missing a bottom cover and has exposed electrical components.
- The conduit that runs out from the building to feed the main gate is not supported in the center of the run and is laying on the ground.
- On the roof there appeared to be a three disconnects that had inadequate Working Space clearances per NEC.
- There are several unsupported and corroded conduits with some completely broken.
- There is one pull box used by main 480-volt feed conductors that is missing covers and very corroded.
Interior
- The Power Rooms’ 1 through 4 electrical equipment looks to be in good condition.
- There are some overcrowding issues with some of the electrical equipment causing potential NEC Workspace issues.
- The Air Conditioners in Rooms 2 and 3 were not running and the one in room 4 was running but not cooling the room.
- In room 2 the lights did not work and there were MCC buckets doors left open. In room 2 there was one bucket that had been modified with a relay or contactor of some kind hanging out it.
- There were a few 480-volt panels in these rooms that are missing fasteners.
- There were a few examples where extension cords have been used as permanent wiring. There were also small electrical enclosures and conduits that had zip ties holding the covers closed.
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Recommendations
- Rewire the flexible cables in the storage room;
- Relocate the 112.5 kVA Transformer and Panel;
- Relocate 480V Panel to be NEC compliant;
- Relocate circuit breaker panel to be NEC compliant;
- Replace the conductors with cable tray and UV rated cable;
- Relocate disconnects on roof.
Load Study Report
This was a cursory load study was conducted based on available data provided by the plant.
- This site had two 34,500 Volt power feeds with the South consisting of two 1,500kVA oil filled transformers and the North consisting of one 1,000kVA oil filled transformer. These transformers reduced the voltage feed to the plant from 34,500 Volts to 480 Volts.
Transformer Power Calculations
- South Power Feed
- (2) x 1,500kVA Transformers
- 3,612.70 Amps available at 480 Volts.
- The South power feed had 3,612.70 Amps at 480VAC available.
- North Power Feed
- 1,000kVA Transformer
- 1204.23 Amp available at 480 Volts.
- The North power feed had 1,204.23 Amps at 480VAC available.
- Usage Data from the Facility’s Utility Bill’s
- South power feed using 584,888 kWH at a 76.34% Power Factor is 922.64 Amps.
- The available current form the South Power feed is 3,612.70 Amps. The load on that feed is 922 Amps which is which is 25.5% of the current available.
- North power feed using 193.437 kWH at a 77.80% Power Factor is 299.41 Amps.
- The available current form the North Power feed is 1,204.23 Amps. The load on that feed is 299 Amps which is 24.8% of the current available.
Conclusions
Both of the power feeds have space available for adding process equipment. It is recommended to perform a detailed load study once the final process equipment is determined and more information on the load capacity is made available. During the site visit for the feasibility study, it appeared that power distribution systems within the plant are in working order with more than half of the MCCs available for added equipment. If you require an electrical assessment at your facility, Pearl Engineering’s Electrical team would be happy to assist you. For more information on Pearl Engineering’s Electrical Assessment skills please visit our website at pearlengineering.com.
