Atch_48-_App_D_RKMF_17-0097_Electrical_REVISED_13Aug19.pdf

ELECTRICAL

SCOPE OF WORK

For

RKMF 17‐0097 Construct Visitor Control Center Building 697

12‐03‐2018 Revised 08Aug2019 Revised 13Aug2019

Electrical Requirements: All low, medium, and high voltage electrical systems installed in Project shall be in strict compliance with Nellis‐Creech AFB Installation Facilities Standards (IFS) Appendix G, Electrical

Requirements. Project specific requirements are as follows:

1. Install complete medium voltage underground electrical service from Nellis AFB Circuit #3 to Visitor

Control Center Building 697.

2. Install new 4way Medium Voltage switch (S3‐110) on Circuit #3 to support VCC. Install switch on west side of Dunning Circle, at approximate location shown on Appendix F Site Utilities Map. Install switch a minimum of 15 feet north of the existing Circuit #9 underground duct system that is parallel to Swaab Blvd. Switch shall meet the following requirements:

a) Install VFI Switch type 9 12. VFI shall be Triphase with Ground type having either EF or KF trip curves.

b) Unit shall be two sided. No fuse type switches are allowed. Main sections 1 and 2 must have oil immersed 200A switch with 200A load break elbow junctions. Laterals (23) to have 200A load break elbow junctions with VFI, one of which will provide power to the new transformer required at the Visitor Control Center.

c) 6‐inch conduits shall be installed for all circuits at this switch. Provide a 6‐inch spare conduit stubbed out and capped 3‐feet beyond the equipment pad. Spare conduit shall be placed on the Perimeter Road side. All conduits including spares shall be routed to a new vault EM81A from switch. Show all dimensions on the design drawings.

d) All MV switches shall be submitted to Base Electrical Engineer at 99CES/CENMP for approval before ordering. See base IFS electrical appendix for more detail on switch and pad specifications.

e) New switch is not to be mounted on or to the vault nor integrated into the vault. Switch is to be approximately 5‐10feet or so from the vault on the west side on a precast pad with handholes underneath the pad windows.

f) Switch detail:

1. Main 1 200A 250MCM 3phase from S3‐090 via EM79 and EM81A

2. Lateral 200A VFI1 existing single phase #2 cable from EM81 via EM81A.

3. Lateral 200A VFI2 new #2 3phase cable from new bldg. via EM81A.

4. Lateral 200A VFI3 spare

Contractor is permitted to change the order of the laterals

3. New Medium Voltage Transformer and equipment shall meet the following specification:

a) 12,470v primary 3phase delta connected with wells for 200A load break elbows and 480Y277v or 208Y120v grounded wye secondary. (Voltage determined by designer).

b) Transformer shall have a factory finish tan color.

c) Provide 3‐nominal 9KV (8.4KV actual) or nominal 10KV (9.0KV actual) MOV in 15KV elbows on B feed connected phase to ground since the project’s transformer is last on a lateral.

d) Transformer to be rated for (preferred) operation at 45degC (113degF) average ambient and with 50degC winding rise instead of the normal ratings of 30degC ambient with 65degC rise, maintaining the average hot spot temperature rating of 95degC. Note that this transformer must be suitable for operating at 43degC (109.4degF) for 12 hours per day with included peaks up to 117degF for 4 hours. Alternate rating is 43degC average ambient with 52degC winding rise.

e) See base IFS electrical appendix for more detail on transformer specifications.

4. Low Voltage secondary requirements:

All standard normal computer workstations shall use 300va at continuous duty in the load calculations and be on dedicated circuit(s) different from general purpose receptacles. Maximum of 4 computer workstations with or without one 6amp printer on a given circuit. Computers with higher demands shall use less computers per dedicated circuit and use 600va or more at continuous duty.

Server computers have different rules. Large fax/printer/copiers shall have dedicated circuits for each unit as the typical power draw for such units is 10 to 14A. A printer server for that printer shall be the only other item on that circuit. All offices shall have at least 1 general purpose outlet not used for computers. Adequate general purpose outlets shall be provided such that all areas in offices, corridors, etc. are within a 15ft cord length for operation of vacuum cleaners or other similar equipment. See project Specification 011100, Section 1.3.4, for additional low voltage electrical requirements.

5. MV conduit requirements:

For New or Replacement 3phase Main line conduits on circuit 3 are to be 5” or 6” Schedule 40 PVC conduit (no EB20 or EB35). Provide second conduit as a spare with pull rope and #10THWN tracer wire. 6” minimum horizontally between OD of conduit. Use spacers/chairs to maintain distance between conduits. If existing is 4” use adapters to go to 6”. Laterals will be 4” if and only if #2 Cu is used therein AND the total cable length is less than 120ft. As the run is greater than 120ft to the VCC, the lateral will use 6” conduits. Major laterals as designated by the base will always use 6” conduits. Top of conduit is to be a minimum of 36” below ground.

6. MV conduits concrete encasement:

All MV conduits shall be concrete encased with 3” of concrete. Use 500psi for unimproved areas.

Use 3000psi concrete minimum under roads and parking lots. Higher concrete ratings 4500psi will be required on surfaces where semi‐tractors and trailers travel.

7. MV cable requirements 3phase circuits:

Any cable replaced feeding on the switch main sections will be replaced with 1 set of 3 (1 per phase) 250MCM 15KV EPR 133% insulation Cu with 1/3 concentric Cu neutrals. Each cable will have an overall jacket. Base does not use triplex cables inside a single jacket. The lateral from the switch to the VCC will be fed with 1 set of 3 phase #2 15KV EPR 133% insulation Cu with 1/3concentric Cu neutrals. Each cable will have an overall jacket. Base does not use triplex cables inside a single jacket.

8. Procedures:

The #2cable from existing S3‐090 to EM79 to EM81 is to be pulled back toward EM81 past the new switch location. Contractor will install a new electrical vault to be labeled EM81A at the approximate location near the switch where the conduit runs to the north and south intersect. The existing 4” conduits from the south will have to be rerouted into the vault. switch using the main sections. The 4” existing conduit(s) from the north will have to be rerouted into the vault. If existing conduits are 4” use adapters to 6” before installing the 90 deg PVC elbows to enter into the switch. 4 sets of two 6” conduits (1 spare conduit in each pair) are to be routed into the switch from the vault.

After switch is installed, this existing cable (single phase #2) is to be trimmed back and terminated on one of the main lateral sections with new 15KV elbows. Terminate the neutrals onto the ground buss.

A new 3phase 250MCM Cu 15KV 105MV EPR insulated cable with 1/3 concentric neutrals is to be pulled from new switch S3‐110 to a new vault EM81A to EM79 to S9‐090 S3‐090.

All cables in the new vault shall be racked, have a service loop, and be firetaped and have permanent type labels installed per base IFS. Conduits entering the vault shall be sealed to prevent water migration into the conduits from the vault.

This portion of the work shall be done on non‐standard and/or weekend hours as the main gate and possibly the houses on Dunning circle will have to be switched over to and run off of generators furnished by project contractor.

END OF REQUIREMENTS