Secondary Distribution - dmelhosp0054

temperature, as required for proper operation of the equipment. When

the equipment cannot be placed indoors, the primary switchgear shall be

located outdoors in a factory- assembled, weatherproof, tamperproof,

walk-in aisle enclosure. Equipment shall be located above the 100 year

flood plain.

(c) The switchgear shall be metal clad. Circuit protective devices

shall be electrically operated, draw-out type circuit breakers. For

primary power supply to mechanical equipment and for service to other

than Patient-care Buildings, use metal-enclosed fused switchgear

line-ups.

5.2.3 SECONDARY DISTRIBUTION

(a) Health Care, Research, Clinical and Ambulatory Care Facilities and

Essential Buildings with l000 kVA or Larger Demand Load: The total

building load (calculated demand kVA plus future growth) should be

served by multiple single-ended unit substations. A transformer shall

not supply more than half of the building load. The maximum transformer

size for 208Y/120 volt systems is to be 750kVA. The maximum transformer

size for 480Y/277 volt systems is to be 1500kVA. Provide integral,

interlocked primary selector switches (not loop feed) and load

interrupter switches with current limiting fuses for each transformer.

(1) The above requirement serves as a guide to the Engineer. Any

exceptions shall be submitted to the VA for review and written approval

prior to proceeding with the design.

(b) Other Health Care Facilities or Essential Buildings with Less than

l000 kVA Load: Use a single transformer with integral, interlocked

primary selector switches and load interrupter switches with current

limiting fuses.

(c) Quarters and Private Dwellings: Each dwelling shall have its own

kilowatt-hour meter, service disconnecting means and panelboard.

5.2.4 ELECTRICAL ROOMS

(a) Definition: An electrical room is an area located within a building

or structure which contains high-voltage transformers, primary

switchgear, secondary distribution equipment with related panelboards

or any combination of these.

(b) Construction: Any pipe or duct system foreign to the electrical

installation shall not enter or pass through an Electrical Room. The

Engineer shall ensure that foreign piping such as water pipes, steam

pipes, medical gas pipes, soil pipes, sanitary drains, storm drains,

A/C ducts and other unrelated systems are not installed in the

Electrical Room. Sprinkler piping serving only the Electrical Room

shall not be considered foreign to the electrical installation and not

pass thru the room and serve other areas. Electrical Rooms shall not be

located beneath toilets, showers, laboratories, kitchen or sinks.

(c) Existing Buildings Waterproofing: Where it is not possible to

comply with medical program requirements, a continuous metal pipe

sleeve or a membrane waterproof ceiling shall be provided below the

5-2

ELECTRICAL DESIGN MANUAL

ELECTRICAL POWER DISTRIBUTION