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Any Pointers on electrical layout for a fabrication rig
Former Community Member
Trying to find the best approach to this problem has the cable trays between the sockets of the units will not cater for large cables above 25mm2 so was looking at having to change the design from a looping cabling system between Main sockets on each floor there are 4 floors in total on the rig to each Power Cluster.So that each Power Cluster have there own Power Supply cable going to them individually so we can look at cutting down the size of cabling to fit the cable trays.But to do this i'm after some electrical layout ideas from the Forum.The starting point of the electrical layout are 3 125A Sockets (ie.400v,230v & 115v) which have an interconnection at two ends (ie Left Side and Right Side) so there is a need for a change-over switch.Then from there on looking at adding a large distribution box for the individual cables to connect to the various sockets of the Power Cluster.
First thought was simply to use larger cable trays (or ladder) - but presumably there's a reason to rule that out?
Having more smaller cables may or may not help - with more cables/circuits you'll hit grouping factors (especially if closely packed) - which will likely demand an increase in cable size - which might undo exactly what you're trying to achieve.
Bus-bar trunking might be another option - but not enough detail to know if that's sensible or not.
I probably haven't pictured this correctly - I'm struggling to see what a change-over switch is needed for....
At present what we have is a looping system where each Power Cluster sits on each floor there are 4 floors in total each cluster has power sockets of 2 of each (ie 2 x 110v,2 x 230v & 2 x 400v) and a 230v 13A Socket there are inputs for the main power on 2 sides left and right so i assumed a change-over switch would be necessary to allow power to run on one side for safety reasons. At present we are told off the client that at anyone time there are 4 Welders using the rig totalling somewhere in the region of 92A and that there is a Milling and Cutting Machine and also a Crane on the 400v system but are told that the Milling & Cutting Machines won't be in operation while the Welders are working. So a cable of 25mm2 to 35mm2 is being used to cater for the loads in use. But the problem is the bend radius on this type of cabling especially with it being armoured cabling.There is not much in the way of space so we was looking at alternative ways of getting around this.
I have looked at the diagram and am still struggling to work out what the change-over switch is needed for. Why does the system need options to feed it from either end?
This is a sketch of the layout of the Power Clusters on the rig.
That's bizarre (at least if I'm reading it right) - I presume the power is fed from the bottom and the rectangles above the "125A sockets" are plugs.
I hope I've mis-understood, otherwise you seem to have a ring circuits with a separate plug on the end of each leg of each ring - so if one plug was unplugged the exposed pins would be live from the other side of the ring (and I don't want to start imagining what would happen if one of the plugs was accidentally plugged into another circuit).
The separate 400V and 230V systems seem odd - it would be more usual to supply both from a 230/400V 3ph&N system (400V between lines, 230V L-N)
Likewise I'm a little surprised if 110V is distributed about the place - rather than having a transformer in each power cluster.
The bottom part of the system are plugs and all of them are plugged into the main power supply leaving not plug bear.Thats the reason we are looking at using a change over switch to eliminate live potential on the other side. Anyway the other big concern is the size of cabling required against the existing cable tray layout that exists has there are fundamental space issues. So we was looking at using smaller armoured cables coming off a big distribution point to suffice each power cluster individually instead of using the loop system that we have at present. Jimmy2Rivers
Looking at the drawing, then you have a 35mm2 cct fed by 2 125A plugs in parallel. This seems a bit under-sized. How do you arrange the fusing for the pair of plugs, and perhaps why are there plugs at all - could it not be hard wired at the ground floor end ?
If of you really do have 250A of load to disconnect and reconfigure, then either cutting the link on the top floor to make this two separated 125A circuits, or connecting the feeds together and using a larger connector examples or if you need flexibility then single pole power lock connectors as used for outdoor concerts etc might be better than some odd change-over switch arrangement. (do you have to sometimes take supply from a genset in the street ? )
Really 125A plugs are not intended to be used this way, and the total loading needs an explanation.
I've also just noticed that according to the diagram two of the rings are supplied with 400V at one end and 110V at the other... (although I presume that's just a slip of the pen).
The whole thing seems so unlikely (including needing three separate 400V/230V/110V supplies) - let alone the complete mis-understanding of how to wire a simple plug safely - I'm having difficultly believing it's actually been implemented like that. If it really has, starting completely from scratch would seem like a good option.
How would you go about laying out the electrical layout for the Welders to operate from?. Bearing in mind this is a mobile rig that can be moved so the plugging in of power from an outside source to the rig is necessary. Its like a long extension lead.
