High rise risers
- Thread starter dsawyer
- Start date
- Status
southernboys
Senior Member
Re: High rise risers
are you talking about bus duct? if so check out art 368
are you talking about bus duct? if so check out art 368
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: High rise risers
Mike is correct the conductors need to be properly supported. He mentioned Kellem grips, we prefer cable support bushings with wooden chocks. These are special long throat bushings with a tapered insulated throat that you drive a wooden chock into after the conductors are pulled. The chocks are made specifically for the number and size of conductors and ordered accordingly.
[ June 10, 2005, 05:21 AM: Message edited by: infinity ]
Mike is correct the conductors need to be properly supported. He mentioned Kellem grips, we prefer cable support bushings with wooden chocks. These are special long throat bushings with a tapered insulated throat that you drive a wooden chock into after the conductors are pulled. The chocks are made specifically for the number and size of conductors and ordered accordingly.
[ June 10, 2005, 05:21 AM: Message edited by: infinity ]
mdshunk
Senior Member
- Location
- Right here.
Re: High rise risers
I was only involved with pulling riser conductors on one high-rise project. For strain relief we had to zig-zag the conductors around wooden spools in the pull boxes every so many floors. Talk about a pain in the rear end. Bolting a Kellems grip in the box or using a strain relief bushing would have been so much easier. I suppose there's a dozen ways to fulfill the requirement.
I was only involved with pulling riser conductors on one high-rise project. For strain relief we had to zig-zag the conductors around wooden spools in the pull boxes every so many floors. Talk about a pain in the rear end. Bolting a Kellems grip in the box or using a strain relief bushing would have been so much easier. I suppose there's a dozen ways to fulfill the requirement.
Re: High rise risers
Using wood, ceramic, or plastic posts in the pull boxes for supportmay seem inefficient, but keeping the taps and splices at each pull box from pressing hard against the cover does reduce short circuits over time. When wires are pressed hard enough against metal the insulation cold flows over time creating a short or ground fault. Same goes for the wires pressing against each other too much.
Using wood, ceramic, or plastic posts in the pull boxes for supportmay seem inefficient, but keeping the taps and splices at each pull box from pressing hard against the cover does reduce short circuits over time. When wires are pressed hard enough against metal the insulation cold flows over time creating a short or ground fault. Same goes for the wires pressing against each other too much.
pierre
Senior Member
- Location
- Westchester County, New York
Re: High rise risers
300.19
"(B) Support Methods. One of the following methods of support shall be used.
(1) By clamping devices constructed of or employing insulating wedges inserted in the ends of the raceways. Where clamping of insulation does not adequately support the cable, the conductor also shall be clamped.
(2) By inserting boxes at the required intervals in which insulating supports are installed and secured in a satisfactory manner to withstand the weight of the conductors attached thereto, the boxes being provided with covers.
(3) In junction boxes, by deflecting the cables not less than 90 degrees and carrying them horizontally to a distance not less than twice the diameter of the cable, the cables being carried on two or more insulating supports and
additionally secured thereto by tie wires if desired. Where this method is used, cables shall be supported at intervals not greater than 20 percent of those mentioned in the preceding tabulation.
(4) By a method of equal effectiveness.
As can be seen, there are multiple methods that are acceptable.
300.19
"(B) Support Methods. One of the following methods of support shall be used.
(1) By clamping devices constructed of or employing insulating wedges inserted in the ends of the raceways. Where clamping of insulation does not adequately support the cable, the conductor also shall be clamped.
(2) By inserting boxes at the required intervals in which insulating supports are installed and secured in a satisfactory manner to withstand the weight of the conductors attached thereto, the boxes being provided with covers.
(3) In junction boxes, by deflecting the cables not less than 90 degrees and carrying them horizontally to a distance not less than twice the diameter of the cable, the cables being carried on two or more insulating supports and
additionally secured thereto by tie wires if desired. Where this method is used, cables shall be supported at intervals not greater than 20 percent of those mentioned in the preceding tabulation.
(4) By a method of equal effectiveness.
As can be seen, there are multiple methods that are acceptable.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: High rise risers
dsawyer,
Actually I tried to insert it into my original post but I was having trouble with the manufacturers website. Glad I could help.
Trevor
dsawyer,
Actually I tried to insert it into my original post but I was having trouble with the manufacturers website. Glad I could help.
Trevor
- Status