When deploying a Trident or PowerBack unit, picking the correct metering head adapter saves time and prevents installation issues. Here’s a simple breakdown to help you choose the right one in the field.
1. Know Your Options
Bridgeport Magnetics offers the following connection components:
| Component Name | Purpose | Notes |
|---|---|---|
| AM Universal Metering Head | Main metering head (1.375″ blades) | Works on any meter socket (ring-type and ringless). On ring-type sockets, use the supplied bushing to fill the extra gap created by the longer blades. Most common / universal choice. |
| AG Short Blade Metering Head | Main metering head (0.875″ blades) | Designed specifically for ring-type sockets only. The shorter blades provide a snug fit without needing a bushing. |
| CL320 Lever Bypass Adapter | Base adapter for lever bypass sockets | Used with AM or AG on top (never alone). Install the CL320 first on lever bypass sockets, then connect either the AM or AG metering head on top of it. |
Important: The CL320 is not used by itself. It is installed first on lever bypass sockets, and then either the AM or AG metering head is connected on top of it.
2. Know Your Meter Socket Type
| Meter Socket Type | Description | Common On | Recommended Setup |
|---|---|---|---|
| Ring Type | Uses a sealing/locking ring to hold the meter | Older homes, many utility territories | AM (with supplied bushing) or AG (snug fit) |
| Ringless | No ring — meter plugs directly into socket | Newer homes & commercial, many territories | AM only |
| Ringless with Lever Bypass | Ringless socket with a bypass lever on the side | Many commercial services | CL320 + AM or CL320 + AG |
3. Follow these steps when choosing your setup:
Step 1: Check if the socket has a lever bypass
- Yes → Install the CL320 Adapter first, then choose either AM or AG on top.
- No → Go to Step 2.
Step 2: Check if the socket is ring or ringless
- Ring Type (has a sealing/locking ring) → Use AM (with the supplied bushing) or AG (for a snug fit).
- Ringless (no ring) → Use AM only.
Quick Reference Table
| Situation | Recommended Setup | Reason |
|---|---|---|
| Ring type meter socket | AM (with bushing) or AG | AM works on all sockets; AG gives a snug fit on ring-type due to shorter blades |
| Ringless socket, no lever bypass | AM only | AG is not designed for ringless sockets |
| Ringless socket with lever bypass | CL320 + AM or CL320 + AG | CL320 is required for bypass sockets; either metering head can go on top |
| AM doesn’t seat properly on ringless socket | Switch to AG (if ring-type) or confirm socket type | Shorter blades on AG often fit better on ring-type sockets |
| Tight meter cabinet or shallow socket | AG (when on ring-type) | Lower profile than AM |
FAQ
Can I use the CL320 adapter by itself? No. The CL320 is a base adapter only. You must install either the AM or AG metering head on top of it when working on lever bypass sockets.
When do I need to use the CL320? Only when the meter socket has a lever bypass. In these cases, install the CL320 first, then add your AM or AG metering head on top.
Should I use AM or AG on top of the CL320? Start with AM. If it doesn’t seat properly or feels too long, switch to AG.
What’s the difference between AM and AG? AM has longer blades (1.375″) and is truly universal — it works on both ring-type and ringless sockets (use the supplied bushing on ring-type). AG has shorter blades (0.875″) and is designed specifically for ring-type sockets, where it seats snugly without a bushing.
Can I use AM on a ringless socket without the CL320? Yes. On standard ringless sockets (no lever bypass), AM is the correct and only choice.
Which setup is fastest to install? On ringless sockets without bypass, AM alone is the correct and fastest option. On ring-type sockets, AG alone is often quickest. On bypass sockets, CL320 + AG is frequently faster than CL320 + AM due to the lower profile.
