Main Supply Conductor question

[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??

 

[Knobhead]

Last time I used one of my master keys was fault finding on a 660V single phase 2.6MVA supply.

Before that I was paralleling 1.6MVA transformers. I’d only just started with the company and was asked if there was a way of defeating the locked key system! As I said my keys are locked in a chest at home.
Close the Bus Section ACB at the same time another guy has his finger on one of the incomer ACB’s trip.
Shout CLOSED
He shouts OPEN.
If it took 2 seconds we were slow!

Yes it’s dangerous (we were exceeding the maximum fault current 50 KA) but at times needs must, RoB2 will tell you how long it takes to go through a kiln controlled shut down, what took 2 seconds would have resulted in two days down time!

Time to hold my hand up. I’m a rotten barsteward!
I closed the BS after I’d checked the feeder currents.
My mate opened the incomer under near 700A load.
If it had gone wrong, he would have copped the full blast!

I’m a rotten barsteward?

I’ve been next to a 3.3KV 1600A ACB when it opened under fault. I needed new underepants!

 

[Knobhead]

I have never seen a room lit like the arc in a 3.3 KV ACB opening under fault!
It is f***ing frightening!

A brilliant blue flash, then everything goes quiet the plant has shut down!
Then it’s think time. Open feeder 1 close BS 1-2 in three 11KV substations! All back and running within ½ an hour!



The brilliant blue flash!
I hold more qualification in photography as I was sponsored by Kodak and Bowens for 10 years.
I couldn’t light a room like that bloody ACB opening!

 

[Hants-Spark]

Tony - Sounds like you've had some fun (is that the right word) in your day, we have a 3.3 & 11KV ring at our place, I've been there when its popped but never within the switchroom itself, a cable fault twice in the same place, joiners didnt have a good day I suspect. Tried to close as fault was unknown to start with but just fired straight through. Out come the diggers

 

[Knobhead]

It wasn’t fun!

I was ---- scared closing the ACB! It would hold, then trip when the system was on light load?

It took me damn near 6 moths to track the fault down. A faulty OLTC unit was causing a 15% voltage rise at the weekends.

 

[Bobster]

I've been in a sub for 2hours with me jamming main contactor for the kiln main drive before.

As you know leaving a hot kiln not turning for longer than 15-20 min starts causing real problems.

 

[Bobster]

And my I really don't like castell key systems. I've always thought anybody with half a brain would figure how to make one.

I've always stuck to fortress systems where I can. Even then I've never had but have seen master keys for fortress systems.

 

[Knobhead]

I've been in a sub for 2hours with me jamming main contactor for the kiln main drive before.

As you know leaving a hot kiln not turning for longer than 15-20 min starts causing real problems.

Bent like a banana!

You wouldn’t believe 1000T of steel and refractory could bend, it does!

 

[Knobhead]

And my I really don't like castell key systems. I've always thought anybody with half a brain would figure how to make one.

I've always stuck to fortress systems where I can. Even then I've never had but have seen master keys for fortress systems.

Simple reason, you can’t get a Fortress Master Key.

I’ve got Castell Master Keys. I made them. As said they are locked away in one of my big tool chests.

They are bloody dangerous! Under no circumstances will anyone else ever get their hands on them. I would be responsible!

 

[Hants-Spark]

Reading the last few threads, it appears masters are obtainable for both Fortress & Castell key systems, a major flaw for both manufactures by the sounds of it. Maybe one system is better than the other but they both serve a purpose, safety, these systems are then complimented by a robust control management system to ensure accidents are prevented. Everyone goes to work happy and leaves work even happier.

 

[brookster]

Reading the last few threads, it appears masters are obtainable for both Fortress & Castell key systems, a major flaw for both manufactures by the sounds of it. Maybe one system is better than the other but they both serve a purpose, safety, these systems are then complimented by a robust control management system to ensure accidents are prevented. Everyone goes to work happy and leaves work even happier.

I don't know about that , not sure I have read and signed the risk assessment for a happiness so until I have I will remain a grumpy bast**d!