Follow the guidelines below if you’re building a home, business or other structure near pad-mounted electrical equipment.
You must maintain at least 10 feet between the front (doors) of any pad-mounted equipment, such as transformers, and other objects. You must maintain at least 3 feet of clearance from the back of the pad-mounted equipment.
Leave at least 10 feet of clearance above electrical equipment. For transformers that handle more than 1,000 kilovolt-amperes (kVA), leave at least 20 feet of overhead clearance.
Ask Idaho Power for clarification if you have any questions.
Combustible structures such as houses, garages and other buildings must be at least 10 feet from pad-mounted transformers. This clearance may be reduced to the 3-foot working clearance from a non-combustible wall. A 10-foot clearance is still required in front, to each side, and vertically of any door, operable window, air intake vent or path of egress located on a non-combustible wall or surface.
Non-combustible walls must have:
- A 1-hour fire rating for most commercial and industrial buildings.
- A 3-hour fire rating for residences and businesses where people might be sleeping (hotels, etc.)
Exception: Non-operable windows (that don’t open) installed in a non-combustible wall require a 10-foot clearance in front but only 3 feet to each side.
If it is not possible or practical to provide the required clearance between electrical equipment and a combustible building, the customer can install a fire-resistant barrier built of non-combustible materials that meets Idaho Power’s requirements and all applicable building codes.
Acceptable fire-resistant barriers are free-standing walls made of brick, concrete masonry unit (CMU) block or concrete that is located between the pad-mounted equipment and a combustible building or other surface.
Consider the following when building a fire-resistant barrier:
- Make sure the height and length of the barrier meet the requirements of each application.
- Allow space for reasonable variations in the size of the equipment in case it needs to be replaced in the future.
- The 10-foot clearance is measured as between the nearest point on the equipment and the wall, opening or path of egress.