Multi-motor wiring in panel with additional branch circuits

[burchie]

Greetings,
I have a situation in which a manufacture is tell me..."this is the way it always has been done".

The panel is to control a compressor unit.
1. Compressor Motor is 100Hp
2. Exhaust fan is 5Hp.
3. Power supply (460VAC to 24VDC/10amps)

Ok here is my question and senerio:
The incomming power is to be connected to a distribution block (correctly sized for the 100Hp motor and then some). The Vendor uses 6 AWG wire to run from the distrbution block to the Motor Starter Coil (M1); the wires are unlabeled but you can see the short run in the panel.
Also from the distribution block a branch circuit is ran from to the Power Supply (240VA) using 16AWG (I noted there was no short circuit protection or fault protection). Vendor tried to tell me that it was my responsibiltiy through the disconnect I provided to the panel.
To continue; The vendor came off the "M1" and branched to a fuse block and then to a Motor Over Load (2MOL) and then to the 5HP Fan Motor
The other parallel connection from M1 was to a Motor Over Load (1MOL) and then to a 100HP Motor.

What I do not understand is how can the manufacture get away with calling my disconnect short circuit and fault protection for the Power Supply and the 100Hp motor and any burn up is my responsiblity? Are these both not code violations or am I reading the code incorrectly?
Mary

 

[xformer]

Greetings,
I have a situation in which a manufacture is tell me..."this is the way it always has been done".

The panel is to control a compressor unit.
1. Compressor Motor is 100Hp
2. Exhaust fan is 5Hp.
3. Power supply (460VAC to 24VDC/10amps)

Ok here is my question and senerio:
The incomming power is to be connected to a distribution block (correctly sized for the 100Hp motor and then some). The Vendor uses 6 AWG wire to run from the distrbution block to the Motor Starter Coil (M1); the wires are unlabeled but you can see the short run in the panel.
Also from the distribution block a branch circuit is ran from to the Power Supply (240VA) using 16AWG (I noted there was no short circuit protection or fault protection). Vendor tried to tell me that it was my responsibiltiy through the disconnect I provided to the panel.
To continue; The vendor came off the "M1" and branched to a fuse block and then to a Motor Over Load (2MOL) and then to the 5HP Fan Motor
The other parallel connection from M1 was to a Motor Over Load (1MOL) and then to a 100HP Motor.

What I do not understand is how can the manufacture get away with calling my disconnect short circuit and fault protection for the Power Supply and the 100Hp motor and any burn up is my responsiblity? Are these both not code violations or am I reading the code incorrectly?
Mary

IMHO, there should be some sort of OCPD protecting the power supply.

 

[Smart $]

I kinda doubt it, but I have to ask: Is this listed equipment?

The only problem I see is lack of protection ahead of control power.

The rest sounds okay, providing the proper size fuses are used for the 5HP fan motor.

PS: I didn't verify wire size.

 

[GoldDigger]

There should be under the NEC, but if this is a listed assembly or the control panel is a listed panel, then the NEC will not directly apply.
Agreed there is no way a single external OCPD can protect the PS or the wiring to it.

Tapatalk!

 

[Jraef]

There should be under the NEC, but if this is a listed assembly or the control panel is a listed panel, then the NEC will not directly apply.
Agreed there is no way a single external OCPD can protect the PS or the wiring to it.

Tapatalk!

If it is not a listed panel (which I agree, sounds as though it isn't), the 16ga feeding the power supply would need to be 14ga because at that point its no different than field wiring and subject to the NEC, which has very restrictive conditions on using anything less than 14ga.

Whether or not it needs an OCPD will depend on the nature of the power supply itself. Some have integral line protection. I have never seen that on (what must be) a 480V line source, but you never know. Some part numbers or photos would be helpful.

Always keep in mind, "this is the way it has always been done" is sometimes just admitting how many times they have been wrong...