Ultimate Guide : How to Install an Electrical Transformer

It can be challenging to install an electrical transformer on a job site, especially if you're not experienced with them. The first thing you should do is to take care of the transformer. Otherwise, it can become damaged and render your power equipment useless.

Safety precautions should be taken and safety equipment provided to anyone working on the transformer. These tips are applicable to both liquid-filled and dry-type transformers. It is essential to know the requirements for acceptance testing. Acceptance tests must be conducted according to ANSI/IEEE and NEMA approved standards.

Placement of Electrical Transformers

It is crucial to consider all safety codes when determining the location of an electrical transformer installation. Installations should not pose a threat to personnel or equipment. It is important to assess the soil characteristics and soil behaviour if the electrical transformer is placed at ground level.

Neglecting to maintain good soil conditions can cause differential settlements that could result in damage to your transformer and electrical connections. The electrical transformer must be installed on a concrete pad with at least 3,000 PSI. It should have chamfered edges 20 inches below each end. The typical base size is 6x7 feet and 12 inches.

A typical concrete base for pad mount transformers with ratings between 75kVA and 500kVA would measure 5 1/2 x 6 1/2 feet and 10 in. A typical concrete base for units with ratings between 500kVA and 2500kVA would measure 8 ft by 9 ft, and 10 in. Thickness

For electrical transformers to be installed inside or above a building, it is important to carefully plan and analyze the load. This will ensure the structural integrity of the design. To avoid collapse in the event of an earthquake or other seismic movement, special provisions must be made for seismically-prone areas. For any condition, it is highly recommended to have a manufacturer-supplied schematic or drawing of the electrical transformer.

How to Install an Electrical Transformer

Before installing an electrical transformer, it is important to inspect for any damage. You should inspect the transformer for visible damage, broken or loose parts, dirt, and moisture. These signs should not be visible and your transformer should be ready for installation.

• Avoid any stress caused by incoming cables to transformer bushings and connections.
• The protective coating surrounding terminals should not be removed. They protect against surface oxidation.
• Protect aluminium conductors as directed by their manufacturer.
• Manufacturers of electrical transformers should give instructions and details regarding torque requirements.
• Only use UL-listed lugs. Follow the manufacturer's instructions on how to attach them.
• Do not install washers between the terminal lugs or the bus bar. This can cause the connection to heat up.
• Allow cables to pass through the appropriate clearance and do not place them in close proximity to blades or coils. Conform to the NEC's minimum wire bending space requirements at conductor terminals.
• NEMA standards can be used to control transformer sound depending on the unit's kVA rating.
• Ground, ground, and don't forget about grounding. Follow the NEC guidelines and verify that the neutral wire is grounded as required.
• Conduct an insulation resistance test to verify the function of control circuits. Be careful. Some transformers are not able to withstand the voltage.
• For continuity, all windings must be checked.
• Before energizing an electrical transformer, it is necessary to conduct an insulation resistance test.
• If you plan to use the electrical transformer in parallel, make sure that all voltages and impedances are correct.
• Before you energize any 3-phase electrical transformer, compare the line-to-ground and line-to-line voltages.
• Once the installation is completed, verify the output voltage of your electrical transformer.