Help identifying screw inside niche

[erickpeniche]

I'm about to replace my old damaged Pentair SAM pool light with a more maintainable Pentair Amerlite. I removed the screw and took out the whole Pentair SAM. Since the light was already damaged because of a water leak, I decided it was useless for me so I cut the power cable a few inches from the Pentair SAM light to use as a fishing cable for the new Pentair Amerlite cable. All I know about the niche is that it's a stainless steel niche, I can't see any signs of the brand or model. Before getting into the pool, I decided to record some video and take some pictures of the niche so I can have a better idea and understanding of the situation before diving into the pool. I found that there is a screw and something that looks to me like a clamp, where the power cable goes through. I need your help to identify what is that screw for and if I unscrew it, will it loosen up the cable so that I can pull it from the other side? Or will it cause water to leak while I pull the cable from the other side? I also thought this might be for the ground cable, but to my surprise, when I removed the light, there was no ground cable attached to the niche. Any help will be much appreciated. Attaching photos of the niche and the mentioned screw


Thanks in advance!

 

[ajw22]

I think what is usually done is remove the light from the niche and pull it up to the deck. Connect a pull wire to the end of the light wire at the junction box. Pull the pool light wire out and the pull wire through. Then connect the new light wire onto the other end of the pull ire and pull the new light wire up to the junction box.

 

[erickpeniche]

I think what is usually done is remove the light from the niche and pull it up to the deck. Connect a pull wire to the end of the light wire at the junction box. Pull the pool light wire out and the pull wire through. Then connect the new light wire onto the other end of the pull ire and pull the new light wire up to the junction box.

Thanks for the suggestion! Is there an advantage of doing the cable fish from the end of the light wire at the junction box vs doing it directly from the cut wire at the light end? To me, the first one involves pulling first from inside the pool then attaching the new cable and then pulling from outside the pool at the junction box. The second one just involves pulling outside at the junction box. I am just trying to save some steps but I am not sure which method will have less risk of the cable fish going wrong and breaking the tapped joint at the middle of pulling.

 

[ajw22]

I think it is easier pulling a new wire with fish tape then trying to pull a new wire with the old wire. You can lube the new wire as it is going in. And if the old wire gets hung up you are not going to ruin the new wire.