<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Jerry:</div><div><br></div><div>I thought splices or connections were forbade in condulettes. This sounds inherently code non-compliant. Do you have information to the contrary?</div><div><br></div><div>William</div><div><br>On Apr 27, 2017, at 4:41 PM, Jerry Shafer <<a href="mailto:jerrysgarage01@gmail.com">jerrysgarage01@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr"><div>Wrenches</div><div>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. </div><div>Jerry</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 26, 2017 at 6:05 PM, Matthew Sirum <span dir="ltr"><<a href="mailto:matthewsirum@gmail.com" target="_blank">matthewsirum@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Greetings William,<br>
<br>
Good point. This is something I always take into consideration. I<br>
have used Class T Fuses in many situations with and without their fuse<br>
holders. In the case of the installation shown in my custom DC Bus<br>
System pictures the wire/cable type and wire management avoid putting<br>
too much physical stress on the Class T Fuses. The #4 AWG conductors<br>
are supported from above and apply very little stress on the fuses<br>
they connect to. The 4/0 AWG cabling is Cobra X-Flex (fine stand,<br>
very flexible) and each of these conductors is secured a few inches<br>
from where they connect to their fuses. Care was taken in making up<br>
these connection and they were all carefully adjusted and inspected to<br>
ensure they would not stress the fuses. I feel really good about how<br>
it all came together. The same care and attention will be needed<br>
whenever these connections are serviced and the fasteners are<br>
torqued/tightened. When well planned and carefully assembled I do not<br>
have concern there will be any issues related to not using the fuse<br>
holder. I also think about this another way as well... Using the<br>
Class T Fuse Holder adds another 2 connections to the circuit. I try<br>
to remind myself that more connections can equal more chance of<br>
issues... Although, if a manufacturer of a Class T Fuse states the<br>
fuse holder must be used with their fuse there could be an NEC<br>
violation by not using it.<br>
<br>
One thing to note about the use of these fuses in this installation is<br>
that they are supplemental over current protection (OCP). Each<br>
positive (ungrounded) conductor connecting to this DC Bus System has a<br>
means of primary over current protection and disconnect on its<br>
opposite end. The battery systems, the charge controllers, and the<br>
inverter/chargers all have circuit breaker disconnects on their<br>
respective positive circuit conductors connecting to this DC Bus<br>
System. I have seen other folks build without having the needed<br>
appropriate means of disconnect and OCP; although most folk are<br>
probably more likely to include the primary OCP, but not consider the<br>
supplemental OCP. The supplemental OCP (Class T Fuses) provide<br>
protection in the event of a fault or short in a circuit between the<br>
Bus System and the other OCP at the other equipment.<br>
<br>
Like many folks I have installed and worked on battery systems where<br>
we install a Class T Fuse directly onto the positive terminal of the<br>
battery bank or via some form of busbar or connector etc. In these<br>
cases not only do we need to take care not to stress the fuse, but the<br>
fuse itself (and added busbar/connector etc) can act like a lever and<br>
along with the mating cable lug(s) create too much stress on the<br>
battery terminal... Potentially damaging the terminal, the inner<br>
battery connection to the terminal, and/or the seal between the<br>
battery case and the terminal. Carelessly tightening the<br>
hardware/fasteners to assemble these items to the battery terminal is<br>
a common way of inflicting damage on the battery as well. I know I<br>
have been involved in some service situations where there was more<br>
stress on the Class T Fuse than I would like to see, but as best I<br>
know there have not been any fuse failures because of it.<br>
<br>
Thanks for bringing up this question!<br>
<br>
Best regards,<br>
<br>
----MATT<br>
<br>
Matthew Sirum<br>
P.O. Box 1227<br>
Greenfield, MA 01302-1227 USA<br>
phone: <a href="tel:%2B1.413.773.0611" value="+14137730611">+1.413.773.0611</a><br>
email: <a href="mailto:MatthewSirum@gmail.com">MatthewSirum@gmail.com</a><br>
<br>
<br>
-------- Original Message Below --------<br>
<br>
[RE-wrenches] Third Radian<br>
<br>
William Miller william at <a href="http://millersolar.com" target="_blank" rel="noreferrer">millersolar.com</a><br>
Tue Apr 25 23:03:03 PDT 2017<br>
<br>
Matt:<br>
<br>
I have a question for you: I have often considered mounting Class T fuses<br>
directly to a bus bar as you have done. Are you ever worried about physical<br>
strain on the fuse itself without a fuse holder?<br>
<br>
Thanks again for all of your input.<br>
<br>
William Miller<br>
<br>
Lic 773985<br>
<a href="http://millersolar.com" target="_blank" rel="noreferrer">millersolar.com</a><br>
<a href="tel:805-438-5600" value="+18054385600">805-438-5600</a><br>
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