working in an excavation (depending on the angle) is a very hazardous activity. Depending on the length, width and depth of the excavation would depend on how many escape points I would put in place. The excavation itself would have to be barriered off (a good few feet from the excavations edge for obvious reasons) this woul eliminate the need for Fall arrest. As for working inside with Fall Arrest I would choose otherwise. If there was a situation where the sides are collapsing/burt pipes leading to floods etc... the the removal of the FA would slow down the evacuation process (have they considered this?) as for the number of ladders, if the excavation was considerably long I would recommend several ladders tied off, this will create a number of egress points. Just for a quick note, no matter the strength or nature of any material (sand, soil or pebbles) if the angle is at 30 degrees then it will never naturally slip (3 meters wide to 1 meter up)

It would be useful to have a better description of this 'excavation' as the previous poster has suggested they come in different sizes and depths. What activity is taking place in these excavations? What method is being employed for ensuring the excavation does not collapse? I am surprised the client has not asked for a copy of the temporary work's design. Excavations in a commercial environment, such as utilities, tend to have such a document. I agree with Ryan, fall arrest equipment is not normally provided in an excavation where there is suitable edge protecting ie barrier, which can also be part of the temp works design. Built in steps are probably the best option, although a tied ladder will suffice in most cases. Without more information on the type of excavation and potential hazards eg confined space, it is difficult to provide specific guidance.