Question 1

Why are dry-type transformers used in hospitals?

Accepted Answer

Dry-type (cast-resin or VPI) construction eliminates the liquid fire risk and oil-handling/disposal burden that come with oil-filled equipment, which is why it's the default choice for transformers installed inside patient-care buildings. Oil-filled equipment conflicts with NFPA 99 and typical local building codes for indoor healthcare occupancies.

Question 2

What code applies to hospital transformers?

Accepted Answer

NFPA 99 (Health Care Facilities Code) governs electrical systems in healthcare facilities, alongside NFPA 70 (NEC) for general electrical installation and NFPA 101 (Life Safety Code) for life-safety provisions. Internationally, IEC 60076-11 covers dry-type transformer design and testing. Flame-retardant components are expected to meet UL 94 V-0, and units carry UL 1561 listing.

Question 3

What fire-rating and clearance is required indoors?

Accepted Answer

Transformers rated ≤112.5 kVA require a minimum 300 mm (12 in) clearance from combustible material, or an approved flame-retardant barrier where that clearance isn't achievable. Units rated above 112.5 kVA must be installed in a dedicated transformer room with at least a 1-hour fire-resistance rating.

Question 4

Can oil-filled transformers be installed inside a hospital?

Accepted Answer

Oil-filled equipment brings a liquid fire risk and an oil-handling and disposal burden that conflicts with NFPA 99 and typical local building codes for indoor healthcare occupancies. Dry-type construction is the standard choice for transformers inside patient-care buildings. Where a healthcare campus needs exterior or site-level distribution outside the patient-care building envelope, that is a different scope — talk to our engineering team about your specific site layout.

Question 5

How is transformer noise controlled near patient areas?

Accepted Answer

Low-noise operation is engineered into the transformer design itself. For installations near or adjacent to patient-care spaces, noise level is a specification consideration we work through with your project team alongside the kVA rating, enclosure, and cooling class.

Hospital & Healthcare Transformers | Dry-Type | Seatrust