Hello all,
In the case of ungrounded system, where the SLG fault current is sensibly 0, or in the case of a NGR, limited by the NGR current, do you typically size the grounding pigtail risers for this limited current, or the maximum fault current (e.g. LLL, LLL)? Consider an ungrounded delta...
The code isn't very practically helpful (NEC and CEC). Are there better comprehensive references?
So I bond a permanently installed platform in a basement that is nowhere near energized conductors? Some clients are concerned about induced voltages for absurb reasons. Do I go through the efforts...
Can someone shed some light on why we would use a 1/6th (or other fractions) than 1/3rd (33%) or 1 (100%)?
I understand that 1/3 (33%) concentric neutrals are used for 3 phase loads and 1 (100%) concentric neutrals for single phase applications. I'm not immediately aware of any applications...
Hello all,
If there is a specification requirement for a "100% HVAC redundancy requirement", what would you consider in terms of redundancy? Let me explain further.
For our particular situation for a small building that contains 2 rooms, each with AHUs capable of handling 100% of the load for...
Generally speaking, who is responsible for the allocation of spare HV cable lengths? By spare I mean that would be generally discarded during the installation process. The designer or the purchaser or installer? (in our case, we are the purchaser + installer!)
My customer gave me lengths of x...
As part of my yearly training, I have been tasked to select something that will in aid my development. I'd like to learn more about the fundamentals of P&C. I would like to get your recommendations on courses that you think are worth taking. In classroom is preferred.
If it was up to me, I'd...
I'm working with a 10, 7.5 and 5 MVA transformer and am wondering if I need to specify CTs for transformer differential? The configuration is actually:
Recloser --> 10/7.5/5 MVA --> MV switchgear with 1 incomer and 3 outfeeds.
I'm not familiar with protection nor with the customer's...
I've taken over as the lead engineer for a project, where I have been assigned to lead the technical success of a turn key project. It's a smaller project for what my company usually handles, but I've already started to find huge mistakes, mostly on the technical side. For example, a UPS system...
Hello all,
Per IEEE 575 (Sec. 7.5.2 Bonding leads) coaxial (concentric) bonding leads are recommended for distances greater than 10m to reduce the surge impedance.
I'm having trouble understanding the application of this recommendation. Some link boxes are manufactured for these concentric...
Hello all,
I'm working for a Canadian engineering company, and I have encountered a number of times where the maximum system voltage is 253 kV (or 1.1 x nominal voltage [230 kV]) and we always seem to get into a discussion if the equipment, which is usually built and tested for 242 kV and 245...
Hi All,
I have a customer specification that calls for a test, or in lieu of a test, a calculation to demonstrate the maximum potential between the transformer core and ground during a transient condition based off characteristics of its surge arresters on both the primary and secondary. The...
Hi all,
A project I now working on makes use of some outdoor equipment with some tight working clearances. A co-worker has proposed to insulate the buswork, which is essentially flat copper bus, to increase safety and decrease working clearances. I disagree with this proposal, but wanted some...
