Spool Insulator
- Secondary spool insulator for low-voltage racks and clevises
- Spool shape takes the conductor in a deep groove, tied with wire
- ANSI 53-1 / 53-2 / 53-3 classes
- Mounts on a secondary rack, clevis or J-bolt
- For service drops and LV secondary distribution
- Brown / grey wet-process porcelain
Technical Specifications
| Catalog | ANSI Class | OD (mm) | Height (mm) | Groove | Mount |
|---|---|---|---|---|---|
| RAX-SP-53-1 | 53-1 | 64 | 76 | Deep | Rack / clevis |
| RAX-SP-53-2 | 53-2 | 79 | 89 | Deep | Rack / clevis |
| RAX-SP-53-3 | 53-3 | 89 | 102 | Deep | Rack / clevis |
| Custom | Other sizes / configurations — send your conductor & structure spec | ||||
Application & Installation
Where it is used
The spool insulator is a low-voltage porcelain insulator shaped like a spool, used on secondary racks, secondary clevises and J-bolts to carry service drops and LV distribution conductors. The conductor sits in the deep groove and is tied, and the spool seats on a rack spindle or clevis bolt.
Installation sequence
- Select the ANSI class for the conductor and rack.
- Seat the spool on the secondary-rack spindle or clevis bolt.
- Lay the conductor in the deep groove.
- Tie the conductor with a spool tie wire.
- Confirm the spool seats square and the tie is firm.
Buyer’s Guide: Spool Insulator
1. What a Spool Insulator Is
A spool insulator is a small, deep-grooved porcelain spool for low-voltage secondary work. It mounts on a secondary rack, clevis or J-bolt and the conductor is tied into its groove — the standard insulator for service drops and LV distribution on poles and buildings.
2. ANSI 53 Classes
Spool insulators follow ANSI C29.3 in classes 53-1, 53-2 and 53-3, increasing in size and groove. Pick the class for the conductor size and the rack / clevis it mounts on.
3. Where It Is Used
On secondary racks (one spool per conductor), in secondary clevises, and on J-bolts at building attachments. It is a low-voltage device — for primary voltages use pin, post or suspension insulators.
4. The Deep Groove
The deep spool groove holds the conductor and the tie wire securely even at the slack tensions of secondary spans. Tie with a proper spool tie so the conductor cannot jump the groove.
5. Mounting
Seats on a secondary-rack spindle, a secondary clevis bolt, or a J-bolt. Order the spool with the matching rack or clevis so the bore and spindle fit.
6. Material
Wet-process glazed porcelain, brown or grey, for long outdoor service carrying the secondary conductor.
