Cl 1 Gp D Div 2 Genset Control Panel

[fcampan1]

I would like to mount an unclassified genset controller (Thomson Technology MEC20) in a Type Z purged enclosure (with gasketed door) locally mounted on the genset. Also locally mounted will be a gas detector with alarm horn/beacon. A sign will read,"DO NOT OPEN PANEL IF GAS IS PRESENT".
Is this design suitable for a Class 1 Group D Division 2 Area? Thanks, F. Campana Houston

 

[nhee]

Re: Cl 1 Gp D Div 2 Genset Control Panel

The genset would seem to be a larger hazard in the classified area than the controller. Are you certain that the installation area is in fact Class 1 Div 2? If so, is there an alternative safe-area location where the genset can be installed?

 

[fcampan1]

Re: Cl 1 Gp D Div 2 Genset Control Panel

It is definitely a Class 1 Group D Division 2 Hazardous Area. It is offshore Gulf of Mexico.
The genset will be designed for Div. 2, such as Shielded Ignition, X-Proof shutdown switches and solenoid valves, insulated exhaust, Div.2 governor actuator, low watt density generator space heater, spark resistant belt guard, rigid conduit with seals and drains, spark arrestor exhaust silencer, T2D generator temp code, and more. There is no alternative non-classified area available.

 

[bennie]

Re: Cl 1 Gp D Div 2 Genset Control Panel

There is not likely a jurisdiction authority responsible for this site. The important thing is to insure safety of operation. A lot of common sense instead of code articles must be applied.

 

[luke warmwater]

Re: Cl 1 Gp D Div 2 Genset Control Panel

I believe this to out of the Scope of the NEC. 90.2
Is there an Engineer designing this??
Are there Federal Regulations to follow??

 

[fcampan1]

Re: Cl 1 Gp D Div 2 Genset Control Panel

Limiting the discussion to this one question for now,"For a Cl 1 Gp D Div 2 Area, would it violate the NEC if I mount an unclassified genset controller in a Type Z purged enclosure (with gasketed door) locally mounted on a genset with a locally mounted gas detector with alarm horn/beacon and a sign that reads,"DO NOT OPEN PANEL IF GAS IS PRESENT". In particular, is the gas detector and sign approach an NEC Code violation? Thanks, F. Campana Houston

 

[fcampan1]

Re: Cl 1 Gp D Div 2 Genset Control Panel

Or is there a procedure for submitting a question like this to the NEC for an official answer? Thanks for your help. F. Campana Houston

 

[bennie]

Re: Cl 1 Gp D Div 2 Genset Control Panel

This does not appear to be a NEC issue. Check for codes involving the petroleum industry.

I worked on some of the modules for the North Slope. These were designed by experienced engineers in the petroleum industry. The unique and specialized application was not in the jurisdiction of the NEC.

 

[nhee]

Re: Cl 1 Gp D Div 2 Genset Control Panel

500.7 (D) would allow a purged/pressurized enclosure to be an acceptable means of protection for general purpose rated equipment installed in a Cl. 1 Div 2 area. The purged/pressurizing system should be listed and installed per NFPA 497 (Type Z). Most kill power upon loss of internal purge pressure. The gas detector/sign would seem to be an added safety precaution which is neither required nor prohibited by the NEC. If the manufacturer of the genset goes through the effort to create a haz area rated genset, shouldn't he provide it with a haz area rated controller?

 

[fcampan1]

Re: Cl 1 Gp D Div 2 Genset Control Panel

I have been advised that NFPA 496 Chapter 2-11 details and explains how to apply a, "Don't open if gas present" label on a purged Div. 2 enclosure. This problem can be avoided by providing freestanding switchgear/genset controls to be mounted in purchaser's non-hazardous control room, but some users want all controls located at the genset in the Hazardous Area.
Div. 2 genset panels are not (readily) available from genset packagers. Thanks for all the advice, my Code question has been answered. F. Campana Houston