Hello All,
The following was asked of me and I have my opinion but prior to voicing it (and biasing other answers) I would appreciate hearing the collective wisdom of this forum.

"With the hot muggy weather, can a lineman wear an Arc Rated short sleeve t-shirt under their rubber gloves and sleeves and forgo the long sleeve requirement? My concern is Arc Flash is about thermal rating and not shock rating and I am not sure the rubber gloves/ sleeves would comply under the Arc Flash rule"

Opinions/statements/discussion/etc.

In my organization, short sleeves would not be allowed under any circumstance.

From Local 47 & Local 1245 California Safety Manual Accident Prevention Rules (Red Book) 2009:

"1.12 - Clothing

(a) Each employee shall wear a long sleeve shirt, long pants and work boots at all times to minimize danger when exposed to live electrical equipment or lines, moving machinery, hot or injuries substances, rough or sharp surfaces, open flames, and explosions.

(b) Employees exposed to the hazards of flames or electrical arcs shall wear approved flame resistant shirts or other FR clothing as specified by the customer.

(c) Synthetic clothing [snip] will not be used under any circumstance."

Personally, I think the "customer" specification thing is a little weak, but most contractors, utilities, and industrial facilities require FR for linemen anyway. NECA/1245 is also a little behind on "FR" vs. "arc-rated" compared to 70E.

While heat illness due to excessive heat and humidity is a serious concern, proper management of this hazard would need to be accomplished by other means.

Edit to add... from a practical standpoint, the rule makes sense to me as a linemen could potentially be exposed to an arc flash hazard at a moment when rubber sleeves may not be required. Do we really expect our linemen to change their shirts when the sleeves come on and off?

It is actually quite common for linemen to wear short sleeved AR materials underneath sleeves. It is not allowed when climbing or as above stated when not wearing the sleeves but sleeves if designed to cover the area not exposed by the arms are quite capable of protecting up to about 35-50 cal/cm2 depending on the brand. This would be the responsibility of the utility to determine the system and assure the sleeves do work to the level of the hazard. I know of no one burned through Class 2 sleeves in arc flash exposures.

This is a highly specialized situation. Many utilities do not allow this.

Another use of Arc Rated Sleeves could be when a worker is operating a disconnect or another device which requires HRC 0 but the worker commonly wears a short sleeved shirt (non-electrician commonly). They might choose an arc rated knit (often cut resistant) sleeve and a glove to operate the device eliminating the need for a clothing change.

Rubber sleeves are not required under IEEE standards EXCEPT when body position requires extra protection. Generally the only time this happens is when working on the middle phase using rubber-glove only techniques when the phases to either side are much too close.

Rubber gloves have been testing and comfortably exceed 40 cal/cm^2. I haven't seen similar test data for sleeves but since they are made of the same materials, obviously they should pass. Thus from a purely technical point of view there is no reason that this wouldn't be allowed provided that the sleeves are tested.