Restoration of Main Base Electrical Infrastructure Industry RFIs 6 - 05182021.pdf

Restoration of Main Base Electrical Infrastructure Response to Industry Questions #6

5/18/21

1. On drawing E-701 - Switch description calls out that G/S-1W2 have a 4-way integrated sectionalizing junction points. On drawing E-505 the termination junction is separate. What is required?

Junctions shall be separate from G/S-1W2 switch as shown on E-505.

2. In general, would it be feasible to stack termination in lieu of termination junctions integrated into the enclosure?

Provide integrated junctions per design.

3. To maintain the 16 kA rating defined for the gear all ways would need to be 600 amps otherwise the gear is derated the lowest kA rated device, in this case it would be the 200 amp bushings. Please clarify.

This is understood. Provide bushings as indicated on the drawings.

4. Drawing E-701, Transformer Schedule Note 2 says to provide gauges in external pad lockable box.

Cannot get external gauges on a Single-Phase Clam Shell Type 1 Pad Mounted Transformer

Gauges shall be provided within the lockable transformer compartment where primary and secondary connections are made.

5. Drawing E-701, Transformer Schedule Note 4 says transformers are loop fed. Spec only calls for a single LBOR ON/OFF Switch. If these are to be LOOP feed, shouldn’t a Loop feed LBOR switch be specified?

Yes, loop fed LBOR switches shall be provided.

6. Drawing E-701, Transformer Schedule Note 4 says provide transformers with elbow arrestors on spare elbows. Generally, only need (1) set for radial feed unit or (2) sets for loop feed if units can be fed in two different directions. Please specify?

Provide single set for radial feed units and two sets for loop feed units.

7. Three Phase Pad Mounted Transformer Spec Section 26 12 19 Sub Section 2.1.1.2.e Arresters are called out as 12 kV, but Spec Section 26-13-00 Sub Section 2.3 for Pad Mounted Switches calls out 9 kV. Clarify which is required.

Provide 12 kV arresters for all medium voltage equipment requiring arresters to be installed.

8. Pad-Mounted Switchgear Spec Section 26 13 00 Sub Section 2.1.7 HV Bushings calls out to provide parking stands. Are parking stands required? Switch is being supplied with 600A dead break bushings and a ground position switch. So, there will be no reason to park a dead break connector as these will only be take off to be replaced or to remove the switch from service.

Ground position switch will not be provided. As stated in an earlier RFI pad-mounted switches will be provided with two position open-close switches only, no ground position will be required.

Provide parking stands as indicated in Spec Section 26 13 00 Sub Section 2.1.7 HV Bushings.

9. Pad-Mounted Switchgear Spec Section 26 13 00 Sub Section 2.2 High voltage Connectors. Are 200A interfaces required?

Provided 200A interfaces for LOAD/FAULT ways as indicated on the individual switchgear schedules indicated on drawings E-701 and E-702.

10. Switch is being provided with ground position that is visible through the viewing window. Are grounding elbows required?

Ground position switch will not be provided. As stated in an earlier RFI pad-mounted switches will be provided with two position open-close switches only, no ground position will be required.

Grounding elbows are not required.

11. Pad-Mounted Switchgear Spec Section 26 13 00 Sub Section 2.3 Surge Arresters. Are arrestors required on the load interrupter switched load ways? According to the E-701 schedule it is only required on the spare ways. Putting arrestors on the spare ways will require that it be closed instead of open or grounded. During a transient it will need to go through the incoming switch to the spare way arrestor to protect the system.

Prove arresters on spare ways and close spare ways.

12. Arresters are different from the Transformers and Pad Mounted Switches (12kV for XMRS and 9kV for Pad Mount SWG). Is this what is desired?

No provide 12 kV arresters for all medium voltage equipment requiring arresters to be installed.

13. Are we required to use guidance system in drilling specs in Section 33.05 23.13(part 3) paragraph

3.1.5 ? This magnetic survey tool locator is very expensive and not necessary for short bores.

Guidance system is not required as long as contractor can maintain an accurate depth of 72” or more below grade and steering the boring head into the approved areas near the proposed equipment.

14. Do you have a preference on what size conduit for primary?

4” Red Impregnated SDR 13.5 ducts for primaries.

15. Spec Section 33 71 02-20 Subsection 3.6.1 indicates provide number 4/0 AWG bare copper grounding conductor in medium-voltage duct banks and conduit systems. Bond bare copper grounding conductor to ground rings (loops) in all manholes and to ground rings (loops) at all equipment slabs (pads). Route grounding conductor into manholes with the duct bank (sleeving is not required). Duct bank details on E-601 or E-605 don’t show 4/0 bare copper grounding conductor. Please confirm if the 4/0 grounding conductor is necessary. Most of the underground conduit is directional bored. 4/0 AWG bare copper grounding conductor is required to be run in all duct or conduits regardless of if they’re in a ductbank, directionally bored or direct burial.

Redact answer provided as part of RFI #5 provided on 5/ 13/2021 - 4/0 AWG bare copper grounding conductor is required to be run in all duct or conduits regardless of if they’re in a ductbank, directionally bored or direct burial.

New Answer - Provide bare copper grounding conductors in all ducts or conduits based on feeder size and type per MV Feeder Schedule on drawing E-503. 4/0 AWG bare copper grounding counterpoise is not required to be run above concrete encased ductbanks.