Electrical specifiers make sure the electrical installations are safe by design. If it’s for a low voltage switchboard, their system responsibilities can be found in IEC 61439-1&2. If the wiring in a building is being specified, then it has to be in compliance with installation standard (IEC 60364-5-52) and calculation standard (CENELEC TR 50480).
So, specifiers have a lot going on and a lot to worry about. Get the wire/conductor size wrong or put in the wrong circuit breaker and you end up with equipment that doesn’t run. Worse yet, it or the whole system may be unsafe.
Adding to the specifier’s burden, it isn’t like the old days when everything was done in an office. Now, a system designer may be out checking on a project’s progress when somebody wants to know if a wiring size change is OK. Providing answers while in the field and without delay is expected.
That’s the situation. What’s the solution?
Well, it would be nice to have “tools on hand” to deal with such calculations. Something that would take in the voltage and current requirements along with the length of the run and environmental conditions and spit out what size of wiring/conductor was needed. And the calculation should be such that the conductor cross-section would meet IEC standards. (That means in square millimeters. Those of you in the U.S.A. will have to make do with conversion tables, like this one.)
In addition, another required tool, ideally, would be one that analyzes circuit breakers and provides a few handy bits of information. One is the coordination between circuit breakers, with one aspect of this being the discrimination that lets the supply side circuit breaker does NOT trip if there’s a fault nearer to the load side and load side circuit breaker is only suppose to trip. If not done correctly (the coordination and discrimination is not considered for the selection of the pare of circuit breakers). In practice, this means that tripping one branch circuit breaker may trip the main one. As a result, everything goes down even though the problem is only in one small part of the total electrical network.
Now, everybody values discrimination or coordination. But, traditionally, getting it right meant looking through pages and pages of tables for the information. That has to be done for upstream and downstream devices. The process is manual, time-consuming, and prone to error. Automating the determination would make things so much easier.
To be sure, cable calculation and circuit breaker coordination or discrimination software has been around for years. But, let me tell you something about software sitting on separate desktops all over the world: it’s difficult to maintain. You have to roll out patches and releases and hope that end users apply them promptly.
The answer, of course, is to go to the cloud; something embraced by the world’s biggest software company. Then you can access tools through a web browser, which means that specifiers can get cable calculations done on a tablet toted into the field. And it also means that circuit breaker analysis can likewise by done in the office or on-the-go.
For an example of such web-based tools, check out our calculators for wiring and circuit breakers click here. Based upon the wiring requirements, the first can generate a bill of materials, which can also be shared via the cloud.
As for the circuit breaker tool, it’s pretty intelligent. For instance, it’s smart enough to figure out what is the upstream device. It looks at which device has the highest rating, makes it the upstream one and then makes all the others downstream. So you don’t have to feed things into it in some carefully controlled fashion. Just throw it all in there and let the tool sort it out.
For more information on these tools that make life easier for specifiers, please visit our electrical calculation tools page.
5 years ago
In your electrical calculation tools you have a cable calculator. Unfortunately it does not have an option to choose steel wire armour for the PE conductor.
It would also be useful to be able to superimpose the cable I2t rating onto the breaker and fuse curves.
When saving the discrimination curves the company logo does not display
after importing it.