Pole Transformer Bracket
- Supports pole-mounted distribution transformers up to 167 kVA single-phase
- Single-mount and double-mount configurations (500 / 800 mm centers)
- Hot-dip galvanized to ASTM A-123 (≥86 μm)
- Bolt-on hanger compatible with standard transformer lugs
Technical Specifications
| Catalog No. | Type | Bolt Centers (mm) | Max kVA | Weight (kg) | Surface |
|---|---|---|---|---|---|
| RAX-PTB-S | Single Mount | 500 | 100 | 8.5 | HDG |
| RAX-PTB-D | Double Mount | 800 | 167 | 12.0 | HDG |
Application & Installation
Where it is used
- Pole-mounted distribution transformers serving residential / light-commercial customers
- Three-phase pole-top banks (3 single-phase transformers on one pole)
- Substation egress transformers on isolation poles
- Rural distribution stepdown stations (12.47 kV to 240/120 V)
- Temporary construction service transformer installations
Installation sequence
- Position the bracket at the pole elevation specified by the transformer drawing (typ. 25–30 ft above grade for residential).
- Through-bore the pole at 9/16 in for the 2 mounting bolts; verify the bracket is level before final torque.
- Lift the transformer into position — this typically requires a digger truck or boom crane.
- Align the transformer’s lug holes with the bracket’s 500 or 800 mm bolt centers.
- Install 4 M20 (3/4 in) through-bolts with double nuts on each side; torque to 200–250 ft-lb.
- Verify the transformer is level and the secondary terminals face the planned drop direction.
Buyer’s Guide: Pole Transformer Bracket
1. When Do You Need a Pole Transformer Bracket?
A pole transformer bracket is the steel hanger that supports a pole-mounted distribution transformer. The transformer hangs from the bracket via two side-mounted lug bolts; the bracket bolts to the pole via two M16 through-bolts. Match the bracket type to the transformer rating: single-mount (500 mm bolt centers) for transformers up to 100 kVA, double-mount (800 mm) for up to 167 kVA single-phase or for three-phase bank construction.
Standard ANSI C57.12.20 transformer lug spacing is 500 mm for transformers up to 100 kVA and 800 mm for 100–167 kVA — this is the same spacing as the bracket bolt centers, so the transformer drops directly onto the bracket. For non-standard transformers (cooperative-spec, European IEC-spec, or oversize industrial), specify the lug spacing at order time. The 8 mm plate thickness is rated for static loads up to 1,500 kg per bracket — well above the weight of even a fully-loaded 167 kVA pad-mount transformer.
2. How to Choose the Right Size
Pick by transformer rating.
- RAX-PTB-S — up to 100 kVA single-phase (most-ordered for residential)
- RAX-PTB-D — up to 167 kVA single-phase or 3-phase bank construction
For larger transformers (250 kVA+ or three-phase units above 167 kVA per phase), pole mounting is rare — these typically go on pad-mount substations. For pole-top three-phase installations, order 3 PTB-D brackets and configure them in a triangle pattern around the pole. 5–7 day tooling for custom configurations, 50-piece minimum.
