G&W Electric GRAM padmount and vault switchgear features load break switching capability with visible break and integral ground position in a totally sealed, submersible, dead front device. The integral ground position eliminates the need to handle any high voltage connections to ground the cable. The switches are designed for use on 3-phase systems with voltages up to 38kV and 900A load break and continuous current. These switches are extremely flexible and are offered in many different styles. Switches are typically sold with the switch operators on the front side. The high voltage connections can be positioned on the bottom, top, or side to ease cable training and installation.
The switches are designed to IEEE C37.71 and C37.74 for load break capability. Padmount enclosures are designed and tested to IEEE C57.12.28 and C57.12.29.
Configurations Chart for GRAM
| # of Ways | One-line Diagram (Horizontal) | Voltage Class (kV) | Close Into Fault (kA asym)/strong> | Catalog Number | Approximate | |
| Width* in. (mm) | Wt. w/SF6 lbs (kg) | |||||
| 2 |  | 15 | 32 | GRAM21-376M-40RP | 29 (737) | 700 (318) |
| 40 | GRAM21-376M-40PI | 32.5 (825) | 600 (270) | |||
| 25 | 32 | GRAM21-386M-40RP | 29 (737) | 700 (318) | ||
| 40 | GRAM21-386M-40PI | 32.5 (825) | 600 (270) | |||
| 35 | 32 | GRAM21-396M-40RP | 29 (737) | 700 (318) | ||
| 40 | GRAM21-396M-40PI | 32.5 (825) | 600 (270) | |||
| 3 |  | 15 | 32 | GRAM33-376M-40RP | 40.5 (1029) | 950 (431) |
| 40 | GRAM33-376M-40PI | 62.25 (1580) | 1400 (635) | |||
| 25 | 32 | GRAM33-386M-40RP | 40.5 (1029) | 950 (431) | ||
| 40 | GRAM33-386M-40PI | 62.25 (1580) | 1400 (635) | |||
| 35 | 32 | GRAM33-396M-40RP | 40.5 (1029) | 950 (431) | ||
| 40 | GRAM33-396M-40PI | 62.25 (1580) | 1400 (635) | |||
| 4 |  | 15 | 32 | GRAM44-376M-40RP | 52 (1321) | 1200 (544) |
| 40 | GRAM44-376M-40PI | 80.5 (2045) | 1800 (815) | |||
| 25 | 32 | GRAM44-386M-40RP | 52 (1321) | 1200 (544) | ||
| 40 | GRAM44-386M-40PI | 80.5 (2045) | 1800 (815) | |||
| 35 | 32 | GRAM44-396M-40RP | 52 (1321) | 1200 (544) | ||
| 40 | GRAM44-396M-40PI | 80.5 (2045) | 1800 (815) | |||
| 5 |  | 15 | 32 | GRAM55-376M-40RP | 63.5 (1613) | 2500 (1136) |
| 40 | GRAM55-376M-40PI | 98.75 (2510) | 2200 (1000) | |||
| 25 | 32 | GRAM55-386M-40RP | 63.5 (1613) | 2500 (1136) | ||
| 40 | GRAM55-386M-40PI | 98.75 (2510) | 2200 (1000) | |||
| 35 | 32 | GRAM55-396M-40RP | 63.5 (1613) | 2500 (1136) | ||
| 40 | GRAM55-396M-40PI | 98.75 (2510) | 2200 (1000) | |||
| 6 |  | 15 | 32 | GRAM66-376M-40RP | 75 (1905) | 2600 (1182) |
| 40 | GRAM66-376M-40PI | 117 (2970) | 2600 (1180) | |||
| 25 | 32 | GRAM66-386M-40RP | 75 (1905) | 2600 (1182) | ||
| 40 | GRAM66-386M-40PI | 117 (2970) | 2600 (1180) | |||
| 35 | 32 | GRAM66-396M-40RP | 75 (1905) | 2600 (1182) | ||
| 40 | GRAM66-396M-40PI | 117 (2970) | 2600 (1180) | |||
| For rotary puffer (RP): Tank depth= 25" (635mm), Tank height = 27" (686mm) | ||||||
| For linear puffer (PI): Tank depth= 34" (865mm), Tank height = 32" (815mm) | ||||||
| *Dimensions are approximate and do not include entrances, gauges, frames, or operators | ||||||
| Voltage Class | 15kV | 25kV | 35kV |
| Maximum Design Voltage | 15.5kV | 27kV | 38kV |
| Impulse Level (BIL) | 110kV | 125kV | 150kV |
| One Minute Withstand | 35 AC kV | 60 AC kV | 70kV |
| One Minute Withstand, Protection Test Rating | 34 AC kV | 40 AC kV | 50kV |
| 15 minute withstand | 53 DC kV | 78 DC kV | 103kV |
| ** Continuous and load break current | 630 Amps | 630 Amps | 630 Amps |
| Momentary current | 40kA asym | 40kA asym | 40kA asym |
| * Fault-close current (3 times) | 40ka asym | 40ka asym | 40ka asym |
| One second current | 25kA asym | 25kA asym | 25kA asym |
| Mechanical endurance, operations | 2000 | 2000 | 2000 |
| * Rating shown for Linear Puffer, Rotary Puffer limited to 32kA asym | |||
| ** Available at 900Amps | |||
