Archive for the ‘Electrical’ Category

A Review of Electrical Installations

Arkin Tilt Architects / Photo Ed CaldwellIf you are planning on building a straw bale home, chances are you will be including electrical services in the structure. Exactly how those services are installed is different in a straw bale home than it is in a conventional home. Knowing exactly how to install electrical service in your structure is important whether you plan to do the work yourself or hire it out to a subcontractor. You’ll either need the skills to install things properly yourself or in order to explain things to your contractor as they likely will not have worked on a straw bale house before.

It’s a lot easier to learn specific skills and building techniques in person with hands-on training, but I will do my best to describe the process to you here, step by step. Everyone loves bullet points, right?

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Mark Your Electrical Runs Well

When installing your electrical wires in the bale walls, be sure to take the time to mark them out clearly, post installation, with spray paint. This allows you to photograph exactly where the wires run. Picture yourself 10 years down the road wanting to cut a new doorway into an exterior wall and not remembering how your wires were run. Perhaps that’s an extreme example, but I do indeed recommend that you mark your lines nonetheless as you will be happy to have such an accurate map one day, no matter what your long term plans for the walls are. After all, once covered in plaster, there is no way to know where those electrical wires are and a stud finder with electrical sensor may not help you much either due to the density of the walls. Chances are it will pick up on the electrical signal just fine, but why take chances when $5 of spray paint and 15 minutes of your time can make certain you know where things are.

I was also asked recently if ADA (Americans with Disabilities Act) requirements are difficult to accomplish with straw bale wall electrical systems because so many people like to lay their wire on top of the first course of bales, which may not meet ADA requirements. Within the requirements, the electrical plugs need to be between 18″ and 48″ from finished floor. The same is true for switches. In the system I build with, this would be no problem as I use 4×4 toe ups and 14″ tall bales. If you think you will not be able to meet the requirements with your bales, then simply install the wires after the walls have been raised and use a chainsaw to cut channels for the wires. This is how I prefer to install my electrical anyway, so no big deal for me!

Okay, back to the marking of your wires. I suggest you mark the runs ahead of time, before you wire, as well as after the walls are wired. The before hand mark up allows you to see where things will run in relation to niche, truth windows, and other wall details. I personally would not want to see an electrical wire run through a truth window, and I imagine the inspector would not allow it anyway! Once the wires are cut in and the walls are prepared for plaster, go over them one last time with some bright spray paint and take a series of pictures. I like to take them from a distance so I can reference their location in the room to something I will still be able to see, post plastering.

Protect your Electrical Boxes While Plastering

It is all too common for plaster to fill up electrical boxes and cause major headaches for the electricians during trim out. To avoid this, be sure to fully tape off all electrical boxes with red duct tape so that they will be well protected. The red helps locate them later should they get fairly well covered with plaster and the duct tape is strong enough to defend against a wayward trowel.

The time spent taping the boxes is well worth the effort as unplugging the small screw holes after the plaster has dried in them is more than a pain in the neck! I am about to try a cool idea on the house I am currently working on and if it works out, I will let you know. I think it may be a great idea for simplifying plastering around boxes as well as creating flush finishes with the trim out. Stay tuned…!

Moving Power and Phone

A house I am building is located on a rural lot that once held a mobile home. That mobile home had power and phone services to it; however, they were old and not suitable for the new, larger home. In addition, the underground pad mount vault for the power was located in the driveway of the new architectural design.

Obviously it would need to be moved. In general, phone and power are run in the same trench so digging up one without damaging the other is all but impossible, even with a great excavator. In this case, damaging the lines was not a big deal because the phone and power both needed to be upgraded. Once the lines were powered down and exposed, they were cut and the new trench was dug. In this case, the power would be relocated first and the phone would be installed in a new trench after the power was turned on. The main priority is always to get power to the site as construction from a generator is expensive and slow.

The biggest thing to pay attention to in moving power and phone is scheduling. The power company and phone company may be as far out as 2 months for new service, so any delays on your part will have huge impacts on the overall timeline. Be sure that you are FULLY ready for the service installs so the power and phone companies have no reason to leave the site and reschedule you. Be sure to install the individual items to the specified requirements of the power and phone companies. In other words, review the specifications for trench depth and width and pad mount size and locations. Sharp scheduling between excavation subcontractors, power and phone companies, and your own crew will be vital to a successful job. Be sure to take pictures all the way along because you may get an inspector who says “go ahead and backfill” and another, two days later who says “I need to see the shading on this trench.” If you have a picture, you can show the inspector the shading (sand on top of the conduit) without having to dig up the line at the risk of damaging your new installation. Remember, inspectors have the ability to ruin your day if they want to. Show them you are organized and want to work with them and they will help you along your journey.

More on Electrical Work in Straw Bale Construction

The conversation about electrical wires continues. Here’s a reply to my last comment that adding extra cost in the form of electrical conduit to an already costly building process is unnecessary.

Comment

Conduit is CHEAP ……. Look at the cost of Romex as compared to conduit and ordinary insulate wire. Conduit functions as your ground lead and thus simplifies your wiring as well as providing a good tight system where wire is invulnerable……..

You might drill into romex… but would have to be pretty stupid to put a drill bit through conduit into wiring inside it…..and if you did, there would be little fire danger. large main supply conduit with regular access makes upgrading and adding circuits easy. Don’t cheap out here if you are doing it yourself…… You don’t save much and end up paying for it in frustration later.

My Reply

My experience has been the opposite in terms of cost. My electricians here all agree that pulling ropes is much cheaper than running conduit and pulling individual wires. You may be right for the do it your self clan, but I disagree for those who will hire the electrician. Also, my electricians have said that upgrading wire happens so little and that additional boxes will have to be placed any way so the conduit would not make it all the way home. So I don’t see why the conduit would be a good idea for the future. I do whole heartedly agree about the added protection conduit brings for the crazy drill operator; however, if the wire is tucked far enough back into the wall (1 1/4+ for plaster plus 3″ into the bale) i think there is little chance of the average person hitting the Romex anyway. I have done a bunch of these houses and that has proved the easiest: Romex style ropes. I am not against learning and trying new ways, as long as they do not increase the cost of the home for my clients.

Labels: Construction Details, Electrical

Electrical Wires In Straw Bale Walls

I 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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