Replacing fuses for MCB's in BMS control panel

[Skindy]

HiI was wondering if anyone can help me. I need to replace the the fuses for MCB's in a BMS control panel. Can this be done? And how would i go about doing this?Many thanks

 

[telectrix]

if i knew what a BMS panel was.......

 

[malcolmsanford]

Building Management System Tel.

Well to be honest anything is possible providing you plan it out and do it correctly. I would say yes it is possible unless for some reason the system configuration calls for fuses to be the protection device, or the fuses are in milliamp.

Really need some more info here

 

[telectrix]

ah, was management that threw me.

 

[Engineer54]

HiI was wondering if anyone can help me. I need to replace the the fuses for MCB's in a BMS control panel. Can this be done? And how would i go about doing this?Many thanks

So, ....what does the BMS manufacturer have to say about modifying there equipement??
I hope this system isn't still in the warranty period, and if not, the client doesn't have a service contract with them.

And i hope to god it isn't the Johnson ''Metasys'' system!!!lol!!!

 

[Deleted member 26818]

What voltage are the circuits protected by the fuses which you wish to change to MCBs?
What are the R1 + R2 values for the circuits?
Oh and what is the rating of the fuses?

 

[Sintra]

You need to be very careful with BMS systems regarding maximum Zs of the circuits protected by the fuses. You could find that by replacing fuses with MCB's your maximum permissible Zs could be halved.

In my experience circuits from a BMS panel have a high Zs due to the internal impedances of the panels circuitry.

 

[Marvo]

I would question why you want to replace the fuses with MCB's in a BMS, it's very possible that fuses offer better protection than an MCB would. Can you give details on the BMS system and the circuits.

 

[Skindy]

Sorry for the delay in getting back to you all.

It's supplied by 415v 3 phase. The fuses range from 2A to 20A. It looks like an old design. I'm used to using 3 phase breakers to protect the circuit, but this has 3 separate fuses to supply one contactor.

Is it possible to upload pics on this site?

Thanks for trying to help me out with the limited info i have provided.

 

[netblindpaul]

Skindy,
How old?
Is the panel CE marked?

 

[Deleted member 26818]

It may be that the panel is supplied by 415V 3 phase, however the circuits will not be.
Depending on the system, and the circuit lengths, they are most likely to be 24V or 230V.
It is possible that they could be 12V or 48V.
You need to establish the voltage of the circuits, and the resistance of the conductors, before considering changing the protective devices.

 

[Engineer54]

It may be that the panel is supplied by 415V 3 phase, however the circuits will not be.
Depending on the system, and the circuit lengths, they are most likely to be 24V or 230V.
It is possible that they could be 12V or 48V.
You need to establish the voltage of the circuits, and the resistance of the conductors, before considering changing the protective devices.

As Spin has noted, most BMS circuits will be 24 volts.... Any out panels that require a power supply, will have a 230V to 24 V D/W transformer incorporated....

Still don't quite understand why on earth you would want to modify a working system???

 

[netblindpaul]

Spin,
if it is a panel to 60204 then they won't be 230, well it's doubtful anyway, 110/48/24 more likely in order to comply.
If it is a distributed system not to 60204 then it may well be 230.
Any panel to 60204 requires a transformer on the control circuit supply regardless of control voltage.