Temporary Electrical System Schematics

[spettitt]

Hello,

 

I'm posting about the drawing and calculation of temporary electrical systems (TES) for events. @klinzey I noticed your thread on another forum, so maybe the below is relevant. I don't have a specific question - but I'm kind of just thinking out loud so if anyone has/wants feedback on it, I'd be up for discussing, as I'm looking at the kind of planning we do and trying to figure out how much of it we move in to Vectorworks.

 

Our company is half Events/Rental of Audio/Lights/Video/Rigging and half Installation of those same disciplines in venues and other buildings. In the installation side, we're more likely to request supplies from the M&E contractor, but for Rental, there is growing awareness of BS 7909 and the need to draw and calculate temporary electrical systems for events.

 

I know there are 'distributor' objects in the Spotlight tools, but really we have no need to draw each distro as anything other than a schematic device. For cable lengths, as much as the tools are good, we can send out multiple tours each week and no one has the time to draw cable routes in Vectorworks to acheive the correct circuit lengths. Really, I just want to type in that value on a circuit, and maybe have the option to derive it from a physical cable route.

 

Having just purchased it, we are soon to start doing more signal schematics for events in ConnectCAD (mostly broadcast/live video systems). I currently do schematics for TES in a generic diagramming program, which is a little lame, but functional. I'm wondering if I can do them inside of ConnectCAD instead. However, we need to see the protection structure inside of each distro, and also have a way of clearly showing cable data, as the cabling in a TES is just as important as the distros. I'm wondering if data tags could do that.

 

I've started trying to make distros in ConnectCAD, so we'll see how it goes.

 

In terms of calculations, I will still need to push this out to Excel to handle the relevant circuit calculations. For me, Spotlight/ConnectCAD doesn't speak enough of the system design parameters at the moment to do that role. Totting up phase loading per distro is useful as a guide, but it's not enough to check a whole system. There are plenty of platforms out there that do this for an Installation context (ElectricalOM being a great one), but I'm not aware of any that do it effectively for the events world.

 

Mainly:

Earth Faults (PEFC at end of circuit, evaluted against whatever RCD type/value is present in the distro but also anything upstream)

Short Circuit Faults (PSCC at end of circuit, evaluated against whatever MCB/RCBO type/value is present in the distro but also anything upstream)

Let-Thru Energy for Faults (for magnetic-hydraulic breakers)

Ipf (the higher of the PEFC and PSCC at start of circuit, evaluated against the Icu of the device(s) fitted in the distro)

Current Carrying Capacity (using correct BS 7671 tables for H07RN-F and PVC socapex, complete with Class 5 derating where needed and correction factors)

Voltage Drop (again, using the correct tables for the cable types, with Class 5 where necessary)

 

I have a (sadly very complicated and sluggish) Excel that allows me to enter up to 1000 loads and 20 distros and produce calculations for all of the above and estimated test result values for site.

 

The headache though is having to make the topology of a system on a schematic match up to the Excel, and for the Excel to be flexible enough to handle all of the different topologies that could be created. I currently manually cross-check Schematic vs Excel, which will probably continue if I did move to ConnectCAD, but one day it'd be nice if they integrated.

 

Cheers,

 

Simon

 

(no idea why it keeps putting the same images again at the bottom of my post?

 

 

Edited October 3, 2022 by spettitt

[Conrad Preen]

@spettittDear Simon 

Thanks for your detailed post. At the moment ConnectCAD doesn’t concern itself with what goes on inside a device. Not saying we won’t go there in the future. But this is heading in the direction of system modelling and I want to do it right and not just for power distribution. 
 

Im on leave right now but when I get back I’ll give your post another serious read through. 
 

Conrad