Jerry: I thought splices or connections were forbade in condulettes. This sounds inherently code non-compliant. Do you have information to the contrary?
William > On Apr 27, 2017, at 4:41 PM, Jerry Shafer <[email protected]> wrote: > > Wrenches > In the event you or some else installed a Class T fuse and you want to > protect it a little more from cable stress, installing it inside a PVC C > conduit body and cover and fastening the cables to the fuse inside that, this > will protect the fuse from stress and metallic contact and you can put a > label on it stating size and type. > Jerry > >> On Wed, Apr 26, 2017 at 6:05 PM, Matthew Sirum <[email protected]> >> wrote: >> Greetings William, >> >> Good point. This is something I always take into consideration. I >> have used Class T Fuses in many situations with and without their fuse >> holders. In the case of the installation shown in my custom DC Bus >> System pictures the wire/cable type and wire management avoid putting >> too much physical stress on the Class T Fuses. The #4 AWG conductors >> are supported from above and apply very little stress on the fuses >> they connect to. The 4/0 AWG cabling is Cobra X-Flex (fine stand, >> very flexible) and each of these conductors is secured a few inches >> from where they connect to their fuses. Care was taken in making up >> these connection and they were all carefully adjusted and inspected to >> ensure they would not stress the fuses. I feel really good about how >> it all came together. The same care and attention will be needed >> whenever these connections are serviced and the fasteners are >> torqued/tightened. When well planned and carefully assembled I do not >> have concern there will be any issues related to not using the fuse >> holder. I also think about this another way as well... Using the >> Class T Fuse Holder adds another 2 connections to the circuit. I try >> to remind myself that more connections can equal more chance of >> issues... Although, if a manufacturer of a Class T Fuse states the >> fuse holder must be used with their fuse there could be an NEC >> violation by not using it. >> >> One thing to note about the use of these fuses in this installation is >> that they are supplemental over current protection (OCP). Each >> positive (ungrounded) conductor connecting to this DC Bus System has a >> means of primary over current protection and disconnect on its >> opposite end. The battery systems, the charge controllers, and the >> inverter/chargers all have circuit breaker disconnects on their >> respective positive circuit conductors connecting to this DC Bus >> System. I have seen other folks build without having the needed >> appropriate means of disconnect and OCP; although most folk are >> probably more likely to include the primary OCP, but not consider the >> supplemental OCP. The supplemental OCP (Class T Fuses) provide >> protection in the event of a fault or short in a circuit between the >> Bus System and the other OCP at the other equipment. >> >> Like many folks I have installed and worked on battery systems where >> we install a Class T Fuse directly onto the positive terminal of the >> battery bank or via some form of busbar or connector etc. In these >> cases not only do we need to take care not to stress the fuse, but the >> fuse itself (and added busbar/connector etc) can act like a lever and >> along with the mating cable lug(s) create too much stress on the >> battery terminal... Potentially damaging the terminal, the inner >> battery connection to the terminal, and/or the seal between the >> battery case and the terminal. Carelessly tightening the >> hardware/fasteners to assemble these items to the battery terminal is >> a common way of inflicting damage on the battery as well. I know I >> have been involved in some service situations where there was more >> stress on the Class T Fuse than I would like to see, but as best I >> know there have not been any fuse failures because of it. >> >> Thanks for bringing up this question! >> >> Best regards, >> >> ----MATT >> >> Matthew Sirum >> P.O. Box 1227 >> Greenfield, MA 01302-1227 USA >> phone: +1.413.773.0611 >> email: [email protected] >> >> >> -------- Original Message Below -------- >> >> [RE-wrenches] Third Radian >> >> William Miller william at millersolar.com >> Tue Apr 25 23:03:03 PDT 2017 >> >> Matt: >> >> I have a question for you: I have often considered mounting Class T fuses >> directly to a bus bar as you have done. Are you ever worried about physical >> strain on the fuse itself without a fuse holder? >> >> Thanks again for all of your input. >> >> William Miller >> >> Lic 773985 >> millersolar.com >> 805-438-5600 >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/[email protected]/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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