We have some WS2811 addressable LED strips. We’re going to power them off of the PDP (and control them with an Arduino), but just realized that with a 20A breaker the LED wire we have would not be allowed (4-pin wire 22awg). So, thinking about using an inline 5A fuse off of a 20A WAGO connection:
Would this be allowed? And would this make the circuit a “<=5A protected circuit” (R57) so our ~22awg LED wire would be acceptable?
The blue box under R56 seems to allow it but I want to make sure.
R56 does not prohibit the use of smaller value breakers in the PDP or
any fuses or breakers within CUSTOM CIRCUITS for additional
protection.
I’d prefer to use a 5 amp breaker directly in the PDP - it would be cleaner - but it wouldn’t be here in time if we ordered it now from AndyMark. http://www.andymark.com/product-p/am-2096.htm And I’ve been unable to find these Snap Action breakers anywhere else.
Isn’t there a rule regarding how exceptions are made for wires that come with a given device? I seem to recall, for example, that CIM motors come with 14AWG wire but you can still wire them to 40amp circuits as long as all the other wires you connect to them are 12AWG or larger.
In-line fuse is allowed. R57 (required wire gauge) does not specify whether it is the fuse on the WAGO connector, or would a subsequent fuse allow a smaller gauge wire after the fuse. At a minimum, you would need to make the fuse accessible for inspection.
As cbale said, R57: “Wires that are … originally attached to legal devices are considered part of the device and by default legal. Such wires are exempt from R57.”
We purchased the LED wire separately from the LED strips, though it is made specifically for LED strips. That’s what made me think it wouldn’t be covered by this exception. But maybe it is? Just don’t want to take the chance of using the wire without a 5A fuse and then finding out it doesn’t pass inspection.
Yes, we would have the fuse next to the PDP for easy inspection.
Question about R57: our team is using a Raspberry Pi as a coprocessor. Plugged into the Pi is a standard microUSB cable, which we stripped the ends of and connected those to a 12V to 5V regulator. The regulator has 22 awg wires going into a wago on the PDP (20A breaker). We assumed upon reading the inspection checklist that we would need to somehow change things (22 awg into 20A is an inspection failure), but since the regulator is a single piece item that still has it’s initial wires, is this likely to be covered under R57?
(I know this is more of a Q and A type question, however, I’m curious about the experiences that teams have had with wire sizes in the pits. We’ve gotten burned before, and I’m leaning towards replacing the wires/breaker anyways to err on the side of caution. However, this requires time and resources that our team doesn’t necessarily have a lot of.)
Pi’s are 5 volt devices. Powering them from the PD board will break them. :]. But you knew that. More seriously typically they are powered from the vrm which is less than 2 amps. We power them directly to the header on the Pi. If you used 22 gauge wire from the power convertor to the PDB board with a 20 breaker–your inspector missed it.
As to the OP question. Fuses are allowed in custom circuits. Reasonable interpretation is after a 5 amp fuse you are on a 5 amp protected circuit. Only the snap action breaker of the type allowed in R54 can be used in the PDB. If you can get a 5 amp one–that would be legal. Last option would be to use a 12 amp output from the VRM. If the draw is less than 500 MA, you can use the one that is powering the bridge.
The R57 exception is: “Wires that are … originally attached …”. So, if the VRM was originally packages with 22 AWG wire (“initial wires”), then that wire can be used. If you needed additional length of wire from the PDP, then that wire must meet R57 rules up to the connection to the “initial wires”.
Good electrical practice rules most of this conversation. #22 wire is not appropriate for the PDP, the small WAGO is more reliable with #18 or larger.
Inline and correctly insulated fuses are appropriate to follow the PDP output if you are using that. Custom Circuit rules prevail for that use.
The VRM will accept #22 wire.
The wires on the CIM motors have high temperature insulation and that is why the smaller wire gauge is provided on those motors (and provided for in the robot rules).