11.1      General Electrical Requirements

11.1.1           UPS Protection

All contract documents for retrofitting, modifying, or new building construction, which involve data jacks, cabling, etc., shall be designed to include, at a minimum, one duplex outlet on a UPS circuit adjacent to each data jack location. This requirement is in addition to any convenience outlet requirements, and is to provide UPS protection for each PC-CPU and future telephone system which is deployed.

11.1.2           Total Harmonic Distortion

A.      In order to minimize potential effects of harmonics from: Frequency Converters (including 400 hertz ground power units for aircraft), and Uninterruptible Power Supplies (UPS) of 30,000 volt-ampere capacity or greater, the technical specifications for each piece of such equipment must include the following requirements:

1.       Harmonics Content: total harmonic distortion (THD) of the input current waveform, as measured at the input terminals where the equipment is connected to the premises electrical system, shall be 30% or lower whenever the load on the equipment is 50% of its rated output or higher, independent of external filters.

2.       Power Factor: the input power factor measured at the input terminals, where the equipment is connected to the premises electrical system, shall be 90% or higher whenever the load on the equipment is 50% of its rated output or higher.

B.      For Adjustable Frequency Drives (AFDs) for motors 25 horsepower or larger, the technical specifications for each piece of such equipment must include the following requirements:

1.       Harmonics Content: total harmonic distortion (THD) of the input current waveform, as measured at the input terminals where the equipment is connected to the premises electrical system, shall be 15% or lower, and the THD of the voltage waveform shall be 3% lower whenever the load on the equipment is 50% of its rated output or higher, independent of external filters.

2.       Power Factor: the input power factor measured at the input terminals where the equipment is connected to the premises electrical system, shall be 90% or higher whenever the load on the equipment is 50% of its rated output or higher.

C.       Branch Circuits: All circuits shall have a dedicated neutral conductor.

1.       The ungrounded and grounded conductors of each branch circuit shall be grouped by wire ties or similar means in at least one location within the panelboard or other point of origin, splice or terminations point.

In addition, for Adjustable Frequency Drivers of 300 horsepower or more or a group of Drives with horsepower adding to the 500 horsepower or more, a system study shall be performed by the consultant to demonstrate compliance with IEEE Std 519-1992 Tables 10.2 and 10.3. The point of common coupling for the study shall be the immediately upstream medium voltage to low voltage substation in the Airport distribution system. If the study indicates that the IEEE standard cannot be met with above THD limits, then the consultant shall specify lower limits so that the IEEE Standard requirements are met.

11.1.3           Approved Testing Laboratories for Electrical Systems

Refer to Volume 3, Section 4.2.

11.1.4           Aluminum Electrical Wire

No aluminum electrical wire shall be permitted at BWI Marshall and MTN Airports.

11.1.5           Final Cleaning of Electrical/Communication/IT Closets

All projects involving modifications to or in electrical, communication, and/or IT closets/rooms shall provide language within the specification requiring the entire area be cleaned by the contractor prior to demobilization, including removal of all debris, surface dust, etc.

11.1.6           Medium Voltage Cable Terminations

Components used for medium voltage cable terminations at equipment connections and splices, such as tubing used for sealing cable jackets shall bear a manufacturer’s name and product series identifier.

Wherever practicable, cold shrinkable tubing shall be specified in preference to heat shrinkable tubing, to minimize potential damage from overheating and need for high levels of workmanship on the part of the installer.

11.1.7           Transformers

11.1.7.1        Transformer Safety Markings

A.      Transformers shall be marked around visible edges with a 2-inch red reflective tape. The tape shall be installed so that 1 inch of material is on either side of the edge.

B.      Existing transformers shall meet the Transformer Safety Marking requirements (Paragraph 11.1.7.1.A) when an existing transformer is in a location where there is a proposed change of use and/or alteration being made either to the area around the transformer or to the space the transformer is serving.

11.1.7.2        Transformer Sizing

Transformers for tenant improvement projects shall be sized on the basis of calculated/demand load plus 25% or the connected load, whichever is higher. The consultant shall submit complete set of calculations and demand factors for both calculated/demand load and connected load as part of permit drawing submission for the approval of MDOT MAA.

11.1.7.3        Transformer Location

No transformer above 10KVA shall be permitted above ceilings.

Exceptions:

A.      Specialty transformers for low voltage lighting, neon lighting, or other similar systems shall be reviewed on a case-by-case basis.

B.      When an existing transformer is in a location where there is no change of use, change of occupancy, or significant alteration either to the space being served or the area around the transformer, subject to the discretion of the Authority Having Jurisdiction (AHJ).

C.       Transformers permitted in writing by the AHJ.