Temperature Limits

[tallgirl]

Greets,

Ignoring all the sections on derating and otherwise observing temperature limitations for insulation and various devices, is there any section of the Code which states that electrical equipment cannot exceed some particular temperature?

Sort of like a "if people are supposed to be able to touch it in order to service it, it can't be more than xxx degrees"?

 

[Gregg Harris]

Greets,

Ignoring all the sections on derating and otherwise observing temperature limitations for insulation and various devices, is there any section of the Code which states that electrical equipment cannot exceed some particular temperature?

Sort of like a "if people are supposed to be able to touch it in order to service it, it can't be more than xxx degrees"?

Nothing in any of the International codes, or the NEC. The only reference to temperature involving human contact is water temperature under IPC and minimum heating temperature of air required for dwellings.

 

[petersonra]

IIRC, there are some general OSHA requirements that require some kind of physical protection from exposure to temperatures over 130F. Guarding, insulation, etc.

 

[SG-1]

The only type of temperature limits I have seen, are for temperature rise . I think it was IEEE standards for switchgear, transformers, etc. For instance, the temperature is only allowed to rise 40 degrees above the ambient.

 

[weressl]

IIRC, there are some general OSHA requirements that require some kind of physical protection from exposure to temperatures over 130F. Guarding, insulation, etc.

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=22617

 

[tallgirl]

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=22617

That response references a document for "heated" equipment. Does that include "equipment that just so happens to get to be more than 130F"?

 

[templdl]

Greets,

Ignoring all the sections on derating and otherwise observing temperature limitations for insulation and various devices, is there any section of the Code which states that electrical equipment cannot exceed some particular temperature?

Sort of like a "if people are supposed to be able to touch it in order to service it, it can't be more than xxx degrees"?

DTDTs for example. UL allows for thew maximum case temperature of 50degC rise above a maximum of 40degC ambient or 90degC which is a piping hot 194degF. That will get your attention.

 

[weressl]

That response references a document for "heated" equipment. Does that include "equipment that just so happens to get to be more than 130F"?

OSHA works this way. They can't -- in practical terms -- address every concievable situation that presents potential harm to an employee, so often they cite seemingly non-applicable rules to show 'intent and recognition of hazard' to rule on a violation. They also have this in the general cause where they require the employee to be protected from any recognizable hazard and make that the employers responsibility by providing a 'safe workplace'.

 

[kwired]

OSHA works this way. They can't -- in practical terms -- address every concievable situation that presents potential harm to an employee, so often they cite seemingly non-applicable rules to show 'intent and recognition of hazard' to rule on a violation. They also have this in the general cause where they require the employee to be protected from any recognizable hazard and make that the employers responsibility by providing a 'safe workplace'.

That would not put a limit on operating temperature, it just requires protecting employees from incidental contact with something operating at a high temperature, a simple shield may accomplish this.

 

[weressl]

That would not put a limit on operating temperature, it just requires protecting employees from incidental contact with something operating at a high temperature, a simple shield may accomplish this.

OP: ""Sort of like a "if people are supposed to be able to touch it in order to service it, it can't be more than xxx degrees"? ""

 

[kwired]

OP: ""Sort of like a "if people are supposed to be able to touch it in order to service it, it can't be more than xxx degrees"? ""

Lockout/tagout applies to more than just electrical energy.

Locking off the electrical energy may be what needs done to ensure the resulting heat from some equipment is at a safe working condition even if no electrical work is going to be performed.

 

[weressl]

Lockout/tagout applies to more than just electrical energy.

Locking off the electrical energy may be what needs done to ensure the resulting heat from some equipment is at a safe working condition even if no electrical work is going to be performed.

Apples and oranges.

 

[GeorgeB]

IIRC, there are some general OSHA requirements that require some kind of physical protection from exposure to temperatures over 130F. Guarding, insulation, etc.

Hmm, makes me rethink my hydraulic solenoid coils which have continuous ratings in excess of 100C ... and anyone can walk up to in many plants, completely unguarded ...