Transformer Clearances
- Thread starter dinkelja
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jcormack
Member
- Location
- Pennsylvania
Depends on the oil type and the material of the building it is close to.
Mineral Oil? High flash-point? R-Temp? Silicone?
The answer will be the largest distance required by the NFPA, NESC, Local Building codes, etc.
Mineral Oil? High flash-point? R-Temp? Silicone?
The answer will be the largest distance required by the NFPA, NESC, Local Building codes, etc.
jtester
Senior Member
- Location
- Las Cruces N.M.
If the cabinet opens towards the building, working space clearances would also apply. Working space clearances are dependent on another set of circumstances beyond oil type, building type, etc. They are often greater than simply equipment clearances.
Jim T
Jim T
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Except for working clearance this is not an NEC issue. You need to check with your building codes and insurance company.
Check the following for some good guidance: FM Global DS 5-4, IRI, NFPA 850 Chptr 3. Containment curb usually needed for potential burning liquid.
Minimum requirements driven by insurance. Utility owned xfmr spacing may not consider other hazards of the facility. Watch for egress doors that may be blocked by burning xfmr.
Minimum requirements driven by insurance. Utility owned xfmr spacing may not consider other hazards of the facility. Watch for egress doors that may be blocked by burning xfmr.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Dave_PE said:
450.27 has rules to follow only if the installation presents a fire hazard. The NEC has nothing in it to define when an outdoor transformer presents an actual fire hazard. The NEC also lists various options but no specific requirements for how those options are implemented.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
As others have said, there are local codes, state regulations, fire codes, utility requirements etc.
As a rule of thumb, if there is more then 500gals of oil, you need to start checking for spill requirements. If less then 500gal, typically spill containment is not required. Something else to watch for is if in close proximity to a building, the building wall will require it to be 2 hour fire rated. Check the IBC or UBC whichever is in effect.
As a rule of thumb, if there is more then 500gals of oil, you need to start checking for spill requirements. If less then 500gal, typically spill containment is not required. Something else to watch for is if in close proximity to a building, the building wall will require it to be 2 hour fire rated. Check the IBC or UBC whichever is in effect.
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