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Non-Segregated Bus Duct (Bus Ducts) vs Cable Bus

Issue Cable Bus Non-Seg Bus Duct - Bus Ducts

Ratings

 

 

Available from 600V to 69KV
800 Amps to 8,000 Amps

 

Available from 600V - 5,000 Amps
5KV and above not readily available and must be custom made. Non-Segregated Bus Duct is generally not available at voltages above 5KV.

Engineering

 

 

 

 

 

 

 

 

Cable Bus is an Engineered System

MP Husky Exclusive - Inductive Reactance Program. Defines for the User and the Engineer the operating characteristics of the Cable Bus run:

The individual conductor current, power dissipated per foot and total.

Individual phase currents, impedance and voltage drops.

Average phase impedance and total 30 power loss.

Non-Seg Bus Duct is an Engineered System.

 

 

 

 

 

 

 

Energy issues

 

High Efficiency Phasing arrangements in result in lowest losses , therefore lower operating costs

Bus Duct has less efficient phasing arrangements result in higher losses and higher operating cost.

Short Circuit Tests - Fault Bracing

 

Tests performed up to 120KA RMS Symmetrical, runs certified for up to 100KA RMS Symmetrical. Can provide greater Short Circuit Bracing if required, up to 200KA.

Tests performed and Non-Segregated Bus Duct runs are certified for up to 100KA RMS Symmetrical.

 

Heat Run Tests

Tests performed

Tests performed have been performed on Non-Seg Bus Duct.

CSA

CSA Certified.

Bus Duct is only CSA Listed

UL

UL Listed

Bus Duct is UL Listed.

Installation Labor

 

 

 

 

 

 

Cable Bus Installation Requires Minimal Effort:
Everything pre-cut to fit specific location. Housing parts are Match Marked to Installation Drawings. Bottom cable support block is factory pre-installed. All hardware is supplied from cable lug to cable lug.

Sections weight are similar to cable tray and are relatively light, easily installed with two men.

Bus Duct Installation Requires Increased Installation Effort:
The contractor has pre-manufactured sections that need to be bolted in place, but the sections are the much heavier than Cable Bus. Bus Ducts usually take at least two people per section.

Non-Segregated Bus Duct usually requires heavy lift equipment, adding additional cost to Bus Ducts.

 

Field Modifications

 

 

 

 

Permitted.
Housing installation accuracy to 0.25" and easily field adjusted, (e.g. shorten the housing or add filler sections to accommodate improperly located items.)

Automatically adds a spare housing section to every order.

Not Permitted.
Non-Seg Bus Duct Housing installation accuracy to 0.0625" and adjustments in field are not allowed - cannot shorten the housing nor add in filler sections to accommodate improperly located items.

 

Conductors

 

 

 

 

 

One continuous CSA and/or UL listed conductor from start to finish. NO JOINTS.

Only limit to length is amount manufacturer can spool on cable reel; lack of armor usually means longer runs possible.

Automatically adds up to 5% more cable in every reel.

Non-Segregated Bus Duct Uses Insulated copper bars (or aluminum).
Multiple joints.
Loose fitting boots supplied for wet or exterior installations; the boots do not seal the joint , allowing water entry and possible failure.

 

 

 

 

Switchgear Terminations

 

 

 

Standard cable termination provision.
Less costly than bus duct entry provision
Provides all cable termination hardware,
including lugs and stress cone terminations.

 

Non-Seg Bus Duct requires more costly switchgear and must have bus risers to within 8" on top of cell. Bus Duct manufacturer must add cost of flex braid for connecting bus ducts to switchgear bus bars.

 

Transformer Terminations

 

 

 

 

 

 

 

Standard Cable Termination Provision.

Less costly than bus duct entry provision. Provides all cable termination hardware including lugs and stress cone terminations.

Can also provide economical aluminum cable termination boxes, making the transformer less costly to buy and simpler to coordinate with.

Ensures there is adequate cable termination space.

Non-Segregated Bus Duct requires a more costly transformer. The transformer termination box must have bus risers to within 8" on top of cell or the Bus Ducts manufacturer must supply a steel box and add cost of flex braid for connecting bus duct to transformer bushings.

 

 

 

 

Fire Stops

Nelson Multi-Cable Transit (MCT)
Absolutely water tight. Three (3) hour rated.

Manufacturer's standard.
Bus Duct Fire rating TBA

Housings

 

 

 

 

 

 

 

Same ventilated top and bottom covers whether indoors or out, allowing use of free air rated non-armored cables.

T6063 Aluminum Alloy is used as standard.

For special applications, housings may be made from stainless steel or hot dipped galvanized steel.

Optional custom fittings are readily available upon request.

Outdoors - Non-Seg Bus Duct is totally enclosed.
Requires bus bar de-rating (i.e. larger bus bars) for exterior portion to make up for lack of cooling. Installer must add anti-condensation treatment to prevent rusting, adding cost. Anti-condensation may take form of breathers & drains or space heaters or both.

Indoors - Non-Segregated Bus Duct usea a ventilated enclosure. When everything is indoors, smallest bar size permitted. When part of run is outdoors, then the indoor portion has oversized bars to physically match up with exterior portion, adding additional cost to bus ducts.

Material Purchasing

One Purchase Order covers the complete material supply from cable lug to cable lug.

One Purchase Order covers the non seg bus duct material supply, but the flexible connectors and hardware are NOT usually included by the bus ducts manufacturer.

Maintenance

 

 

None - Owners may want to IR Scan terminations during annual maintenance.

 

Annually IR Scan Bus Duct terminations and joints.

Annually torque the Bus Duct joints.High cost relative to Cable Bus.