Main Supply Conductor question

[brookster]

Personally I would have used SWA.

 

[JIM4179]

From what I am told there are no bends.
The set to the 400 A board are 240mm tri rated
For the 600A board there are 2 x 240mm tri rated in parallel
Although these will not cover the 1000A from the ACB they are enough to carry the maximum Current able to be pulled from the respective boards.
As Tony has stated the main issue is the MPFC

The Regs do have a section ( sorry not with me at the moment ) that adds that if mechanical protection is provided and a minimal risk is present then certain safety measures need not be applied, however I still believe that Current Carrying capacities and MPFC have to be covered?

 

[Knobhead]

We're well out of the realm of BS7671 with this.

The ACB out going tails must each be capable of the full fault current. Two 400mm² per phase would be about right if they were run in trefoil formation. The trefoil formation is solidly clamped together to stop magnetic influence causing damage.

Each phase of the ACB out going terminals should have four 400mm² tails per phase. Two to each of the sub panels.

Sorry to spoil you're day but you have to be aware of the danger of this set up.

 

[guest119]

Is the acb to be cranked down? IE .8 .6 etc.
What is to be the type setting IE b,c,d?
Has diversity been applied to the 600 plus 400 to allow the acb to be cranked down?
Having asked the above it dont really matter because the whole idea is just nuts to me.(and others)
The people who are designing it for you dont seem to know what they are doing, from your descriptions.

Boydy

 

[Knobhead]

Is the acb to be cranked down? IE .8 .6 etc.
What is to be the type setting IE b,c,d?
Has diversity been applied to the 600 plus 400 to allow the acb to be cranked down?
Having asked the above it dont really matter because the whole idea is just nuts to me.(and others)
The people who are designing it for you dont seem to know what they are doing, from your descriptions.

Boydy

It's late, try sobering up! Then re-read the thread.

 

[Guest111]

If I were you I'd be very wary this doesn't come back and bite you, as Tony stated magnetic repulsion under heavy fault current can do some nasty things. Think about what happens when a steel cable snaps under load,then imagine that level of force as a whip being cracked,a bit of thin trunking is not going to hold it,that's why busbar chambers are thick steel and the busbars are clamped down tight.

 

[benji]

the only current ratings i can find for tri-rated are for installing in free air so trunking seems out,you could use tray with parallel feeds to both boards all in trefoil or equally spaced

 

[Engineer54]

So no protective sub-main (distribution) devices after the 1000A ACB then, oh dear!! As stated above, this sounds like a lash-up job, and one that you need to be very careful about!! This installation is crying out for a main switchboard arrangement, that can also incorporate the change over switch, which i'm assuming now, is for a stand-by generator?? Is this proposed C/O, Auto or Manual operation?? To go any further, I / we need photo's of this existing installation.

 

[brookster]

Sometimes the C/O is part of the generator set up (doesn't matter if its not really), there would always be a main switchboard (fused) which could provide normal service, direct mains and to kill the gen so you can maintain the stuffs.
Cant imagine there would ever be a case of a standy being installed without the necessary means to control it!
SWA is much more friendly with gen set ups bin the trunking :smart:

 

[Engineer54]

Several ways of combining a changeover switch into an existing system. In this case i'm pretty dammed sure, that this is going to be a manual system. lol!! which in itself is going to call for some sort of captured key system, as it stands at the moment!!

 

[Hants-Spark]

I really do think a picture of the current layout would assist here, as Eng54 has mentioned if a manual C/O is to be used then a castel key system or similar is a must. From the previous post IMO this has trouble written all over it, and possibly someones A*&e on the line when things go wrong.

 

[Knobhead]

The better system is Fortress keys. I’ll be amazed if E54 hasn’t got Castell master keys, mine are locked away. I’ve never worked out how to make a master Fortress Key.

 

[Hants-Spark]

The better system is Fortress keys. I’ll be amazed if E54 hasn’t got Castell master keys, mine are locked away. I’ve never worked out how to make a master Fortress Key.

Thats' fair enough, I've only ever worked with a Castell system so my knowledge of other keys systems is limited.

 

[Engineer54]

The better system is Fortress keys. I’ll be amazed if E54 hasn’t got Castell master keys, mine are locked away. I’ve never worked out how to make a master Fortress Key.

I haven't as it happens!! In fact i can only just about remember the last time i worked on a manual key interlocked system. ..lol!!

All the main MV/LV Switchboards i've worked on for many years now, have been fully auto control, (with load shedding facilities when required) be they dual source mains supply or otherwise, and with or without stand-by generators. A far cry from my training day's when most dual source supplies were in the main, manual. Certainly on the MV side of things anyway, it was a real pain going round switching and releasing captured key's on those old oil filled RMU's we had around the plants!! lol!!

 

[Hants-Spark]

We're still using Castell's on our site, it is a pain releasing keys etc but keeps you fit, and do I need the exercise
Nothing new for the OP then, has he given up on this one??