busway question 2

[mel127]

Greetings,
We are on the process of upgrading various equipment(switchgears,busducts,generator controls,etc) to better improve the system.But due to budget concerns the management tried save something like instead of totally replacing the busways (3 phase , 3000 Amps , 4160V) they are pursuing to replace only portion of it(only the connecting fitting to the switchgear).My questions are:
1. Is it OK to just replace portion of the busway?Im not familiar with the construction of this.How are the fittings connected?Are they bolted,welded?I know this is silly question but there is no way i can verify the since they are energized.
2. Thus this involve reinsulation of the busbars?If so is there any special insulation to be used/purchase?

This busway/busduct was built a long time ago. I cannot even read the label on it.

Thanks in advance

 

[7anoter4]

Try these

http://findarticles.com/p/articles/mi_m0PIL/is_2004_Oct_26/ai_n6253481

http://www.allbusiness.com/energy-utilities/utilities-industry-electric-powerity/6358308-1.html

 

[mel127]

Thanks 7anoter4 for th link.

 

[dpmac]

Many of the older US medium voltage 4160 and 15kV class bus ducts I have seen are quite simply insulated (most times)copper bus bars in a metal enclosure. Rather simple stuff once you take a closer look at it. Depending on the voltage, type of construction and environment they can last quite a while.

Some manufacturers used a machined GPO-3 fiberglass bracket to mount the bus bars. Hard to purchase replacements but easy to have made. Others simply used standard 6.25" standoffs and clamped the bars in place. Both 3M and Raychem (USA) make a nice heat shrink sleeving for any standard size bus. We are refurbishing a 45 foot 15kV 3000A outdoor bus duct this weekend. They have refurbished (new bus insulation, paint, gaskets and the occasional standoff) a 20 to 40 foot section each year to limit the impact to the budget.

I would believe it would be less expensive to refurbish in place then replace with new. 3000A would probably consist of two (2) 1/2" x 6" bus bars per phase. 3M Sleeving is about $15-18 per foot. So you looking at $100-$120/circuit foot in sleeving alone. Depending on geographic location and bus duct location (indoor, outdoor, elevated, hidden, etc, labor costs may high. Our little project will take (3) men one 16 hour day plus scaffolding costs.

Joints are typically bolted together with standard hardware and spacer plates. The joints could have simple boots, taped or worst case but rare, epoxy poured joints.

It may be worthwhile to take a look inside (safely of course) and see what you have.

Hope this helps.

Pat