Hiko U-PILLAR Underground Service Connection Box

The Hiko U-Pillar is a new concept in service connections for branching and looping networks. Building on Hiko’s expertise in underground switchgear, the U-Pillar delivers a simple, robust, secure, cost effective and fully underground solution for 63 A / 100 A service fuses and 160 A DIN standard disconnects.

In the U-Pillar, fusegear is locked and protected below ground level in an air chamber, where it is kept clean and dry, even in flood conditions.

The unique design also provides for safe and convenient inspection and maintenance above ground level, without the need to pump out water.

Another key feature of the U-Pillar is the free movement of air around the fusegear, which eliminates concerns around operational safety and long-term reliability associated with other underground solutions that rely on so-called “waterproof” fuse housings. These typically include seals that may be vulnerable to the pressure cycling that occurs as the temperature of the service fuse varies between hot and cold. When air is drawn in, moisture condenses inside the housing, and is not expelled when the fuse heats up again. Water in contact with a fuse causes operational hazards, reduced asset lifetime, and elevates the risk of in-service failure.

The U-Pillar comes complete with water-blocked, pre- terminated flexible tails for both the incomer and service supplies, so network operators can be certain that the integrity of the asset is not compromised by water ingress via a damaged or poorly maintained service cable. And service connection contractors do not need to open the box.

The reinforced lid of the U-Pillar is extremely robust, for installation in footpaths and driveways.

The pit is shaped to provide structural strength and long-term stability. Materials used are benign to the environment, and resistant to engine oil, petrol and diesel.

U-PILLAR MODELS – BRANCHING NETWORKS
Hiko Code	Description	U-Pillar Design Image
UDPxx02x063/100xx	63A 1 to 6 way/100A 1 to 4 way
UDPxx02G160xx	160A 1 x 3P
UDPxx02x100Cx	100A 1-to-3-way conduit

U-PILLAR MODELS – LOOPING NETWORKS
Hiko Code	Description	U-Pillar Design Image
UDPxx02x063/100Lx	63A 1 to 6 way/100A 1 to 4 way
UDPxx02G160Lx	160A 1 x 3P

U-Pillar Features

• Current rating from 63A to 160A
• Single or four core connections for branching network
• From 1 to 6-way service connection
• Single core connection for looping network
• U-Pillar is an Arc Initiation Protected Zone
• IP: IP4x / Flammability: UL94
• Service connection: single phase or three phase
• Looping maximum current rating: 230A
• Dimension: 375mm x 375mm
• Lid load: class B and D
• Designed to have an air chamber (water bell principle) for switch gear to guard against underground water level
• Unique design provides a “pull up” feature to allow inspection, maintenance and later connection above ground level
• Conduit U-Pillar also provides 1-to-3-way internal connection solution for drive way and footpath
• Service cable can be changed to any three directions of U-Pillar

Mechanical Specifications

Materials

Branching Connection

* Incomer cable has two options – single core cable 25mm² or 4-core cable 25mm²

Conduit Connection

* Incomer cable has two options – single core cable 25mm² or 4-core cable 25mm²

Looping Connection*

*Looping CU cable maximum size 70mm² and maximum looping current rating 230A

Options

• Security bolts / internal padlock
• Identification (on lid and bell)
• Incomer and service cable tail lengths (0.2 m and 0.5 m as standard)¹
• Branch joint²
• Service fuses
• Street lighting and other auxiliary supplies

Notes

1. Capped incomer and water-blocked service connectors included as standard
2. Hiko product code KP8033 (Pfisterer ISICOMPACT single-shear-bolt connector and resin joint kit) for main 50-240 / branch 10-70mm²

U-Pillar article in ElectroLink Jul/Aug 2023

Other literature available on request

Reports, drawings, technical data sheets, installation instructions, O&M guidelines