125 VDC Site Visit Questions and Answers

125 VDC Site Visit Questions and Answers

FA9101-08-B-0030

1. In the Statement of Work on page 11 under paragraph 4.4 it mentions personnel computer(s). Who will provide the computers?

The computers referred to in SOW are existing machines. Providing a new PC or laptop is not in the scope of work for the project.

2. One of our suppliers has asked for a clarification concerning the output for the battery chargers. They say that the “IDC Out” in the chart shown under Specification 3.9.3.C on page 11 in the Statement of Work looks like the AH rating on the battery, not the charger output, but they’re not sure. These are very large charger sizes for the required batteries. The think that a typical “IDC Out” for these batteries would be about 12 – 25 amps instead of what is shown in the chart. Please clarify what the “IDC Out” should be for the four battery chargers.

Minimum of 20A IDC Out

3. LAN Cabling: How far away is the termination point for the LAN cable?

Refer to section 3.8.4 page 9 of SOW.

4. LAN Cabling: How many walls will need to be penetrated to run the conduit?

Number of walls can be determined from drawing package.

5. LAN Cabling: How thick is each wall and what is the probability of hitting rebar or structure steel? Minimum thickness is 8 inch concrete block. Reinforcing bars are present in walls and floor, avoid cutting of rebar or structural steel.

6. LAN Cabling: Is firestop required, and if so, what brand?

Yes, 1 hour rated firestop, Hilti Construction Chemicals or equal

7. Rectifier Replacement: What is the size of the AC source cables supplying the rectifier? Refer to Statement of Work paragraph 3.6.1 and 3.6.2. The contractor can field verify existing details during the site inspection.

8. Rectifier Replacement: What is the location and breaker assignment for the rectifier source power? Refer to Statement of Work paragraph 3.6.1 and 3.6.2. The contractor can field verify existing details during the site inspection.

9. Rectifier Replacement: How long are the cables from the point where they enter the rectifier to where they terminate in the rectifier?

Refer to Statement of Work paragraph 3.6.1 and 3.6.2. The contractor can field verify existing details during the site inspection.

10. Rectifier Replacement: What size/type of lugs are on the DC output cables?

Refer to Statement of Work paragraph 3.6.1 and 3.6.2. The contractor can field verify existing details during the site inspection.

11. Monitor/Inverter: What type of anchoring is to be used for the monitoring device and the inverter? Existing units are rack mounted. Racks can be bolted to the wall or floor mounted

12. Monitor/Inverter: Does all cabling from and two each unit need to be in conduit? Existing Monitor/Inverter installations are adjacent and contained within the same rack and no conduit is used for the interconnections. If the two units are located separately then conduit between them would be required.

13. Batteries and Spill Containment: Do the new battery stands need to be stepped like the existing ones? Yes.

14. Batteries and Spill Containment: Is an Epoxy type spill containment system require, or can it be bladder type system? Spill containment system installed under rack with neutralizing absorbent pads is preferred. If not an epoxy floor coating and barrier to contain electrolyte is required.

15. Who’s providing the AC connection to the new charger (customer or vendor who won the job)? Use existing AC cable. Cable terminations made by vendor.

16. Battery room temperature is over 85 degrees F and there’s no ventilation. Its’s dangerous for flooded batteries to be in a closed room because of hydrogen build up, also the new batteries will not last with this temperature. Are there any air conditioning or ventilation installation improvement at this location? No

17. What’s the maintenance window hours (2300-0500)?

Outages for maintenance must be scheduled through ATA

18. Can the old strings and chargers be replaced during the day or it has to be in a maintenance window? Must be during an approved outage

19. Can we power down the charger and then install the new plant or the existing power system need to be running constantly during the change out? See page 3.8.1. Short Outages will be required to connect portable backup and to remove and connect permanent system.

20. Can we use the overhead crane in building 879?

It can be used but shall be coordinated and operated by ATA personnel

21. The Statement of Work requires us to install a monitoring system. Where is the alarm termination panel and how far? Refer to section 3.8.4 page 9 of SOW.

ATA will determine LAN cabinet location at each site.

22. Do you want spill containment quoted? Yes

23. Are we utilizing the same conduit for AC and DC runs? No, DC shall be installed in separate raceways.

24. Rectifiers in the same locations? Yes

25. Run new DC and AC cabling? New DC only.

26. Is the batteries hold in circuits or do they only throw breakers?

Refer to Statement of Work paragraph 1.2 for typical 125VDC loads.

27. Is AC run and tied to the new rectifier by contractor or facilities electricians.

Contractor shall provide AC connection to the new rectifier.

28. Where is the LAN connections located.

Refer to SOW paragraph 3.8.4 for distances. Exact location TBD.

29. Who is making final LAN connections.

ATA, network personel will make the final connections to the LAN. Cable will be ran to the final location, coiled and left for final installation.

30. What size and type cable for DC runs. Size accordingly based on AH rating at an 8 hour rate. Size cable based on allowable ampacities listed in the NEC, latest edition

31. Room 922 says 480 1 phase for the rectifier. Is this really 277 to neutral.

AC input to the charger is 480V, 3 phase.

32. Building 879 can the overhead crane be used?

It can be used but shall be coordinated and operated by ATA personnel.