When testing balaclavas with face shields or with goggles, we typically do not tuck them since the act of tucking or not tucking is dependent on the worker and the material it is tucked into. However, best practice is to tuck in the balaclava. This keeps the arc rated balaclava from exposing the neck; however, we have never seen burns from not tucking in a balaclava. I have seen burns 2 times from underneath an arc flash bee keeper’s style hood, but in one case the hood was blown off.
The NFPA 70E committee considered requiring balaclavas be defined as “covering the mouth and nose”, but the committee rejected this for several reasons.
So since the committee didn’t believe that the balaclava definition should be changed, we recommend wearing safety glasses, an arc rated shield to the level of the hazard, and a balaclava arc rated to the hazard with the chin covered in arc flashes up to 12 cal/cm² as recommend by NFPA 70E Annex H.3. There is no guidance in OSHA 1910.269. This is how we teach balaclava donning in our electrical safety classes, including the Low Voltage NFPA 70E Arc Flash Training Class and our OSHA 1910.269 Arc Flash Awareness Class.