A rigger and I have gotten into a debate on my current project. We're adding a vertical mast of truss on each side of the apron of our stage and putting a 68' long cross-member on top with additional lift lines to the roof structure. For all intents and purposes, this is a permanent structure. Temporary only in the sense that we could remove it in a painful process of hiring in outside contractors to do it. The only time that might happen is if over the course of the next several decades, we need to hang significantly heavier loads or it is eventually deemed structurally deteriorated and needs to be completely replaced.
We have 8-circuit connector strips on either side of the apron that are inaccessible and unusable. Those circuits we plan to tap and put onto the truss.
The district electrician and I want to pipe conduits of the dimmable circuits out of J-boxes next to the connector strips, up to the beams of the roof structure, and then down to the height of the truss. They would not be physically connected to the truss. From here, 19-pin panel mount connectors would take the electrical into SO multi-cable with break-outs that we could move around as is needed. The multi-cable would have appropriate strain relief grips, also suspended form the beams.
What the rigger wants to do is make custom 8-circuit SO multicables with 2P&G breakouts for the circuits from the connector strips and use a break-in on one end, and the breakout on the other, running no new conduits. The cable would drape up to the roof beams and over to each vertical mast.
Additionally, he wants to take (12) circuits from the dimmer racks and pipe them through the wall in our mechanical room directly onto our catwalk. At our catwalk, a 12-outlet 2P&G plug box would allow for (12) SO cables to individually carry the circuits from the catwalk, in a bundle, to the truss. The cable run would drape down from our catwalk to the truss, with pick-points on to the roof structure beams. Then, the cables would be laid out to have female connectors on 5' centers along the length of the truss.
My electrician and I have several problems with this. SO cable is specifically not allowed for permanent installs for a reason - it dry rots. If my electrician remembers code correctly, SO is only an acceptable use in permanent installs when the flexibility is needed (such as drop boxes) (again, he's verifying this in his codebook when he gets back to his office tonight). Also, in a bundle, they would need likely need to be derated (he's checking his codebook on this for confirmation). Plus, this structure is to be considered permanent for us. The rigger is defending his position by claiming that it is a temporary structure and the cables would be allowed. He did not understand why they would need to be derated. He also claims it provides more flexibility for us because we can add/subtract cables from the catwalk to the truss as is necessary. However, we don't have a lift to get to this cable bundle 35' in the air, and the last thing I need to deal with is having the risk of 2P&G connectors getting disconnected when 19-pin connectors could be screwed on and would almost never need to be looked at.
This is our rigger's way of providing inexpensive power distribution. Granted, we really don't want to spend a boatload of money on a 12-circuit, 60' connector strip, but I think it should not become flexible cable until at the truss. Anything that is a completely permanent cable run (e.g. the 12-cable SO bundle bridging the gap between the catwalk and the truss) should really be in conduit.
Experienced riggers and code-junkies -- what are your thoughts?
Flexible cable bundled together or rigid conduit between the catwalk and the truss?
To derate or not derate?
(12) 2P&G connectors or (2) threaded 19-pin connectors?
I've already gotten into two arguments with the rigger on this, and my electrician agrees with me that a pile of flexible cable for a might-as-well-be permanent install is a poor chose. Additionally, the rigger has had the project manager for a local electrical contractor quote the project for him -- this is the electrical contractor of choice between my electrician and I, but we also understand that theatres aren't his thing and his familiarity with Article 520 of the NEC is shady, at best. We think the project manager may have deferred to the rigger for expertise on the electrical that is misguided. I've tried to contact said project manager, and he has not returned my call.
I really don't need this causing this big of a problem, because this electrical contractor is the one we would hire no matter what, but if he gets caught in the middle of this rigger and his ways, this is going to be a messy situation. Especially because we have multiple riggers quoting this project but already have this electrical contractor as our established go-to guy.
The rigger has already told me he can quote the project without electrical, but that we need to then find someone else who has experience with rigging, rig the electrical on the truss. (Speaking of which, how much experience do you need to get flexible cable on a fixed truss? -- This seems to me like it's an empty threat of sorts)
We have 8-circuit connector strips on either side of the apron that are inaccessible and unusable. Those circuits we plan to tap and put onto the truss.
The district electrician and I want to pipe conduits of the dimmable circuits out of J-boxes next to the connector strips, up to the beams of the roof structure, and then down to the height of the truss. They would not be physically connected to the truss. From here, 19-pin panel mount connectors would take the electrical into SO multi-cable with break-outs that we could move around as is needed. The multi-cable would have appropriate strain relief grips, also suspended form the beams.
What the rigger wants to do is make custom 8-circuit SO multicables with 2P&G breakouts for the circuits from the connector strips and use a break-in on one end, and the breakout on the other, running no new conduits. The cable would drape up to the roof beams and over to each vertical mast.
Additionally, he wants to take (12) circuits from the dimmer racks and pipe them through the wall in our mechanical room directly onto our catwalk. At our catwalk, a 12-outlet 2P&G plug box would allow for (12) SO cables to individually carry the circuits from the catwalk, in a bundle, to the truss. The cable run would drape down from our catwalk to the truss, with pick-points on to the roof structure beams. Then, the cables would be laid out to have female connectors on 5' centers along the length of the truss.
My electrician and I have several problems with this. SO cable is specifically not allowed for permanent installs for a reason - it dry rots. If my electrician remembers code correctly, SO is only an acceptable use in permanent installs when the flexibility is needed (such as drop boxes) (again, he's verifying this in his codebook when he gets back to his office tonight). Also, in a bundle, they would need likely need to be derated (he's checking his codebook on this for confirmation). Plus, this structure is to be considered permanent for us. The rigger is defending his position by claiming that it is a temporary structure and the cables would be allowed. He did not understand why they would need to be derated. He also claims it provides more flexibility for us because we can add/subtract cables from the catwalk to the truss as is necessary. However, we don't have a lift to get to this cable bundle 35' in the air, and the last thing I need to deal with is having the risk of 2P&G connectors getting disconnected when 19-pin connectors could be screwed on and would almost never need to be looked at.
This is our rigger's way of providing inexpensive power distribution. Granted, we really don't want to spend a boatload of money on a 12-circuit, 60' connector strip, but I think it should not become flexible cable until at the truss. Anything that is a completely permanent cable run (e.g. the 12-cable SO bundle bridging the gap between the catwalk and the truss) should really be in conduit.
Experienced riggers and code-junkies -- what are your thoughts?
Flexible cable bundled together or rigid conduit between the catwalk and the truss?
To derate or not derate?
(12) 2P&G connectors or (2) threaded 19-pin connectors?
I've already gotten into two arguments with the rigger on this, and my electrician agrees with me that a pile of flexible cable for a might-as-well-be permanent install is a poor chose. Additionally, the rigger has had the project manager for a local electrical contractor quote the project for him -- this is the electrical contractor of choice between my electrician and I, but we also understand that theatres aren't his thing and his familiarity with Article 520 of the NEC is shady, at best. We think the project manager may have deferred to the rigger for expertise on the electrical that is misguided. I've tried to contact said project manager, and he has not returned my call.
I really don't need this causing this big of a problem, because this electrical contractor is the one we would hire no matter what, but if he gets caught in the middle of this rigger and his ways, this is going to be a messy situation. Especially because we have multiple riggers quoting this project but already have this electrical contractor as our established go-to guy.
The rigger has already told me he can quote the project without electrical, but that we need to then find someone else who has experience with rigging, rig the electrical on the truss. (Speaking of which, how much experience do you need to get flexible cable on a fixed truss? -- This seems to me like it's an empty threat of sorts)