Electrical Wires In Straw Bale Walls

Written by Andrew Morrison

ground fault interrupterI have been a member of a straw bale list serve for quite a few years and every so often an interesting conversation emerges. This one is an ongoing debate about the safety of running electrical wires through straw bale. I’ll keep you posted as this conversation evolves. (The comments of other people are in italics.)

Initial Question

I’ve been kinda wondering lately about the potential desirability of having all electrical circuits in bale walls protected by arc fault breakers. Where I live, circuits serving bedrooms are required to be arc fault protected. I’m thinking that any/every outlet box in bale walls might be well served if they were arc fault protected since if there is a fault that generates a lot of heat – the straw might ignite and smolder for days before anyone notices a problem.

Any thoughts? Downsides? (The cost is about $20-25 more than a standard breaker. Seems like cheap one time insurance…)

First Reply

If you mean ground fault interrupt breakers, they aren’t going to protect against generating a lot of heat (regular breakers do that).

What they do is ensure that the current isn’t traveling a path other than the wires themselves. If you have a circuit which is arcing to ground, they would trip for that.

The downside to GFCI is that they can sometimes trip for large motors with large startup currents. This is one reason they aren’t mandated for all circuits.

Note: I don’t think it is a great idea to bury wire in the straw bale at all. If something goes wrong you need to rip apart your wall to fix it, or even if you want to change it. I would put wire in chase (say a baseboard) interior to the walls.

My comments on this issue:

I agree with the idea of placing wires in a chase to some extent; however, there will always be wires in the bales as switches and plugs are located within them on at least some walls. If this is true, then running wires in a conduit or chase, if not already a necessity to the design, would be a waste of time and money. Sure you get to access the majority of the wire along the path should something go wrong, but you still have to rip up the wall to fully service it.

More importantly, how often do you anticipate needing to replace your wiring? In most cases, and I mean MOST, there will never be a reason to replace the wiring as long as the owners live. For me, adding cost to an already expensive building for such a “possibility of necessity” is a bad idea. Again, if the design supports it, great! We did a house where all the bale walls were up on an 18″ pony wall on the second story to get above the roof line of the first floor. That made an awesome chase for wiring and actually saved the client money because the electricians could simply pull all their ropes through a big open space behind the pony wall. They loved it! So, work within the design and pay attention to the cost of adding little details when they are really not necessary.

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8 Responses

  1. At 3:30 PM, Kristina said…

    I don’t think one would ever need to change out regular electrical wiring but with the rate of change in the computer industry, I’m wondering if Ethernet cable, TV Cable, and telephone cable might need to be replaced after a few years. I know many people have had to have their T.V. cable rewired so they can get digital signals.

  2. At 5:00 PM, Andrew Morrison said…

    Yes, that is a good thought. In such cases, it is a good idea to run conduit in the wall so that new lines can be pulled in the future. Metal conduit or blue plastic both work well and each have their advantages over the other.

  3. Hi, I’m a computer geek and I have a couple thoughts on this. I would run two cables, one to say the area’s you might want TV so livingroom or den and perhaps the master bedroom the second cable I’d set up outlets in areas where you could attach wireless routers to serve the area without being in the way. Bandwith speeds are such that wireless is just as good as cable these days.

  4. has anyone run MC cable instaed if romex? It’s a little stiffer and it seems it would stay put during construction.

  5. Hi Mike. MC Cable has been used and does work. I find there are two issues with it. First, it has more metal in contact with the bales that is subject to condensation issues. Secondly, it is more expensive and ultimately, not necessary, so could be considered wasted money. Third, you have to notch much bigger channels to accept it so it takes more time to install. That said, some people choose to use it and see happy with the results. Hope that helps.


  6. How much per square ft does it cost to do the electrical wiring?? Does it compare to standard construction Cheaper more expensive??

  7. Hi Scott. It depends on the electrician, but in most cases, it is a bit more expensive than conventional work because there is more labor involved. I would expect no more than a 10% price increase in most cases at the top end.

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