| Author | Message | ||
| Jim Stewart (H3jim)
Rating: N/A |
As I am running some wires around the bus, the air conditioner compressor lines run right where I want to go. It is tempting to tie wrap some wires to the foam insulated lines. Not however, if they get way too hot. The wire is good to 105 C., the tie wraps are good to 185 F. I am running R134 for refrigerant. | ||
| Marc Bourget Rating: N/A |
Compressor/condensor lines or lines to/from the Evaporator? The Evap lines should be ok, IIRC, some condensor lines may get above 105 deeg Celcius. This comes from a recollection. I didn't check Smead's books first. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I believe the 105 C. rating is above an ambient temperature of probably 40 C., not an absolute temperature rating. Richard. | ||
| Jim Ashworth (Jimnh)
Rating: N/A |
The rating is for absolute temperature. if ambient is 100C, the amperage capability is severely reduced since the wire warms further with electrical flow. Boiler rooms require higher temp insulation so that the wires can handle the "rated" amperage at the elevated temperatures. Marc- That is the most obnoxious smiley I have ever seen. Too bad the edit time has expired for you to remove it. Jim | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
If u are putting the wires within wireloom or some other protective jacket, tie-wrap them right to the a/c lines. Along the outside of the foam insulation on the piping the temp. will be barely distinguisable from ambient of the space. I presume you are using wireloom or another protective jacket, right, Jim, given the area where the wires will be? | ||
| Jim Stewart (H3jim)
Rating: N/A |
Jim, I am running 4 jacketed cables, 3 of them are boat wire, the last being the remote control cable for the inverter. They should not be sujected to direct physical abrasion in this location, although it will be subject to water and the elements. My intent is to secure them well enough so they don't chaffe or have a chance to vibrate and fatigue. I tried using 1 1/2" drain pipe as a sheild, but they are too large to jam in. Maybe with more patience I could get tehm to fit, but its tight. I may get a stick of 2" conduit to try, if its available in plastic in that size. The wires are a 1" round, 4 conductor, 6 gauage (to and from the inverter), a 1" flat, 2 conductor 6 gauge (main 24 volt line to house fuse block), a two conductor 16 gauge(generator auto start), and the 25 conductor for the remote. I do use extra protection when going through any walls. The foam is old and has several small areas where it is not there to allow room for the pipe hangers. The lines are 1" copper going from the compressor to the condensor coils. | ||
| Jim Ashworth (Jimnh)
Rating: N/A |
H3jim- 120vac and lo-volt dc should not be in the same conduit. A 1/2" air space should separate ac & dc wiring. They can cross closer than 1/2" but not run parallel together. If the entire run is in conduit(s), don't use jacketed cable for the 6/4 or 6/2; use individual THHN stranded wire. The 6/2 for the 24v house wire will handle the equivalent of 100a of 12vdc. That is an awful lot of electricity for the lo-volt loads on the house circuits. You might be able to use a smaller wire. Temperature is not going to be an issue here due to the a/c pipes and insulation, so whatever way you decide to run them, you don't need to run hi-temp wire. I prefer conduit even though it is a little more work initially. Keeps everything neat and IF you need to run another wire later (did I really forget that circuit?  )it is real simple to push another conductor in the pipe. Good luck with this. Jim | ||
| John Jewett (Jayjay)
Rating: N/A |
Jim A. , you're correct that it is not necessarily a good idea to put AC/DC in the same conduit, but there is no specific provision in the NEC prohibiting it. The only caveat is that all wires (or cables) have insulation rated for the highest voltage present. i.e. if you use 600V AC rated wire (THHN/THWN etc.) you can run 12 VDC in with your 120/240 VAC. I'll not delve into such associated gremlins as capacitive reactance, inductance, capacitve loops etc. ...JJ | ||
| James Maxwell (Jmaxwell)
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H3: Since it is all jacketed, have at it, and I see no problem. I may hear flak from the purist here, but I see no logical reason for running conduit when u can buy jacketed cable for most applications. Where the wiring is exposed to extremes of weather and elements or road conditions, like thru a wheel-well or under the bus, yes, I see the need for conduit and the protection offered, but not within the bus. | ||
| Jim Stewart (H3jim)
Rating: N/A |
I was using a conservative rating on the wire, the DC can have a significant amount of voltage drop. I am running a 24 volt DC refrig, 16 cu ft, so it can draw a pretty good current when both compressors are running. I was also going to use this wire for the 24 volts that goes to the equalizer, so it would power all 12 and 24 volt house items. Certainly a small wire could carry the ampacity, but voltage drop creates heat, and lessens the efficiency of all the applications. can't really get too big for the DC. At this time, I have not run the wires in conduit, just tie wrapped them together and supported them using anything convenient, such as the parallel air conditioner pipes. If I do use conduit, I would at this stage probably cut a slot lengthwise so I can just slide the wires in. Helps with cooling, still keeps them neat and mostly oprotected. they are fully protected cables in there own right, and as long as they are supported along their runs, do not require conduit. Also for an equivalent size of wire, the boat cable is much more flexible and easy to use than anything else I have tried, so the only down side was a couple more $ for the wire. Thats not much when I compare to the fuel I will be using going to Bus N USA. The control cable for the SW remote, is also shielded. That leaves a question if the generator auto start (current / no current) gives me phantom starts, then I would need to give the wire some room. But it seems the consesus is to not worry about the heat. Thanks | ||
| Jim Ashworth (Jimnh)
Rating: N/A |
JJ- NEC Article 551-5 (c), (3) covers the 1/2" separation. Mine is an older code book but this should get you close to the rule. H3jim- A big concern is that the 24v line will pick up some ac hum that may show up in the CB or dash radio. My inverter when charging puts a slight hum in the CB and the water & holding tank monitor. Kind of annoying. Since the wires are in, according to your description, don't worry about them. Anchor them well so they don't move and get on with the rest of the coach. Jim |