Author Topic: Electrical wiring for Timber Frame House  (Read 1444 times)

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Offline carp.andrei

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Electrical wiring for Timber Frame House
« on: April 12, 2021, 12:52:56 pm »
Hello eevbloggers!

I need your oppinion in the following matter:

I'm planning to build a timber frame house, and this building system is not very well known in my country, in Romania.

So, I was wondering how is the electrical wiring done elsewhere, where this system is more widely used.

From the company that is going to install the electrical wiring I got two options: metal tubing (metallic kopex?) with individual wires, or a special, fire retardant, cable (don't remember the code by heart) to be use without any additional protection.

Can you please share some of the practices used in your houses, for those who have Timber frame houses?

I'm still searching through the Romanian regulations on this topic, but I can't say I'm much wiser now.

So, your help is much appreciated!

Thank you in advance!
 

Offline jpanhalt

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Re: Electrical wiring for Timber Frame House
« Reply #1 on: April 12, 2021, 01:16:44 pm »
This Old House is an American public TV series (https://www.thisoldhouse.com/concord-barn ).  Seasons 11 and 30 dealt with a barn rebuild and a pre-FAB timber-frame house, respectively.  I saw the first in its entirety and don't recall anything specific about electrical wiring.  There may be other shows in the series that address adding electrical wiring to solid walls.

Timber frame, including the barn reconstruction, and log construction present similar challenges for in-wall electrical service.  My current home is log up to the second floor.  Feeds to the first floor are either from the basement or roof and drilled through the logs.  The interior walls are all tongue and groove fitted wood.  Of course, any add-on circuits after construction are difficult to do.

In the US, surface wiring conduits are available and are more attractive and more easily modified than rigid conduit or EMT.   I do not like any flexible cable (e.g., Romax) if it is exposed.

As you suggest, whatever you do must comply with applicable codes.  One thing worthy to consider:  Anything with wood timbers will make noises as the timber dries out and develops cracks.  As an epilogue to the barn show, This Old House revisited the owners several years later.  They mentioned overall satisfaction and being occasionally surprised by the noise.
 

Offline hexreader

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Re: Electrical wiring for Timber Frame House
« Reply #2 on: April 12, 2021, 01:22:05 pm »
Disclaimer: I am no expert...

As far as I know there is no difference in code for Timber frame vs traditional construction in UK.

Maybe there is some difference in Romania. I think you need expert advice from somebody qualified in your country, not opinions from random forum members.
 

Offline mvs

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Re: Electrical wiring for Timber Frame House
« Reply #3 on: April 12, 2021, 02:04:16 pm »
From the company that is going to install the electrical wiring I got two options: metal tubing (metallic kopex?) with individual wires, or a special, fire retardant, cable (don't remember the code by heart) to be use without any additional protection.
Metal tubing is not that oft used in residential houses nowadays. NYM-J cable or individual H07V-U wires in a flex plastic tube are more common, at least in Germany.
 

Offline madires

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Re: Electrical wiring for Timber Frame House
« Reply #4 on: April 12, 2021, 02:15:58 pm »
NYM-J cable and pattress boxes for switches, sockets and room distribution.
 

Offline CaptDon

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Re: Electrical wiring for Timber Frame House
« Reply #5 on: April 12, 2021, 02:23:45 pm »
Probably 95% of homes in the U.S. are wooden frame interiors and as such would be subject to fires in the walls and so forth. We have certain rules about wires run in walls and through wooden rafters and those laws help protect against possible shorts from nails being driven into the walls or metallic objects eventually cutting through the wiring such as clothes hangers hanging on basement wiring. With all of that said the laws requiring outlets and switches to be housed in protective boxes within the walls and correct wire sizing with proper ampacity protection should result in ZERO fires. Sadly when doing things cheaply we had outlets and switches that allowed a 'friction fit' of the wiring and was called 'back stabbing' where the wires were not secured around screws but simply 'pushed in' to the device and with time the wires would have less physical pressure to hold low resistance connections and with heavy loading sure enough you would have a fire in a wall and those are the worst. If all of the National Unified Electrical Code rules are followed there should never be an electrical fire and you could build your house from styrofoam and not worry.
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Online themadhippy

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Re: Electrical wiring for Timber Frame House
« Reply #6 on: April 12, 2021, 02:39:05 pm »
Quote
or a special, fire retardant, cable
The  2 main types in the uk are pyro/micc or fp2000, fp2000 is much easier to work with and doesn't require specialist tools  ,but it doesn't offer as much mechanical protection as pyro.
 

Offline wizard69

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Re: Electrical wiring for Timber Frame House
« Reply #7 on: April 13, 2021, 11:47:53 am »
Timber framing isn't really the problem here, it is how the walls are constructed that will cause you the most grief.   Some Timber frames use pre constructed wall panels that may or may not have ready made provisions for electrical.  Some may use walls built up in a more conventional manner, which means plenty of time to install the electrical hardware.   It would not be unheard of the have a combo of the two, especially if interior walls are considered.

I think the key here is planning.   If you are going with large pre fab'ed panels you will want to have the fabricator provide provisions for the electrics if at all possible.

There are a lot of other considerations too, for example will the house have a cellar or crawl space or perhaps just a slab.   If cellar is it expected to be a finished cellar or just a utility space.   In other words there are all sorts of questions to be asked and answers considered.   A timber framed house with a cellar would allow for fairly easy install of electrics (depends upon the specifics of the installation) even in a house built with prefabbed walls with no electrical provisions.  Outlets for example would be feed from the cellar up into the wall.   The electrician could handle it like "old work" using the tools for that type of installation.

In some case you may need to embrace conduit and wire ways.   Follow code but generally you will want conduit or wire ways everywhere the wiring will be exposed.   

running out of battery but hopefully this gives you insight.   
 

Offline tkamiya

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Re: Electrical wiring for Timber Frame House
« Reply #8 on: April 14, 2021, 02:11:36 pm »
Electrical code/regulations are different in different parts of the world.  In US, it's different from state to state.  Unless you have Romanian rule book, you are taking a big risk.  I'm almost inclined to say hire someone to get it done.  Or consult/hire someone locally and work with him/her. 

I do have an electrician license from Japan.
 

Online tooki

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Re: Electrical wiring for Timber Frame House
« Reply #9 on: April 14, 2021, 03:46:04 pm »
Hello eevbloggers!

I need your oppinion in the following matter:

I'm planning to build a timber frame house, and this building system is not very well known in my country, in Romania.

So, I was wondering how is the electrical wiring done elsewhere, where this system is more widely used.

From the company that is going to install the electrical wiring I got two options: metal tubing (metallic kopex?) with individual wires, or a special, fire retardant, cable (don't remember the code by heart) to be use without any additional protection.

Can you please share some of the practices used in your houses, for those who have Timber frame houses?

I'm still searching through the Romanian regulations on this topic, but I can't say I'm much wiser now.

So, your help is much appreciated!

Thank you in advance!
Bear in mind that while there is certainly plenty of knowledge on this topic here on eevblog, this is an electronics forum, not an electricians’ forum (they’re different vocations that have a relatively small amount of overlap in practice). So an electricians forum or the electrical section of a builders forum might get you better information.

As far as what you’re allowed to do, as others have said, the regulations vary a lot from country to country anyway, so your very best bet is to find the website where your country’s electricians hang out.
 

Offline vad

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Re: Electrical wiring for Timber Frame House
« Reply #10 on: April 14, 2021, 10:06:55 pm »
One thing that distinguishes timber frame houses from masonry buildings is that the timber houses get easily on fire and burn down really fast.

Electricity is one of the most common causes of residential house fires.

Therefore, I strongly recommend hiring licensed  electrician who has knowledge of local electrical/fire codes, and has experience in wiring timber frame houses.
« Last Edit: April 14, 2021, 10:16:54 pm by vad »
 

Offline MadScientist

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Re: Electrical wiring for Timber Frame House
« Reply #11 on: April 14, 2021, 10:21:29 pm »
goggle "romania house wiring regulations" , my second search item was a EU copy in english of 2010 regs
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Offline james_s

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Re: Electrical wiring for Timber Frame House
« Reply #12 on: April 14, 2021, 10:24:52 pm »
Refer to local electrical and building codes first, you're going to have to follow that no matter what. Then come here and post specific questions, along with what the code says and we can try to advise you. I have a lot of wiring experience but it is USA-centric, and there's a good chance that if showed you the way I do something, it wouldn't be legal there.
 

Offline vad

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Re: Electrical wiring for Timber Frame House
« Reply #13 on: April 14, 2021, 10:28:29 pm »
Having said that, in the United States both individual THHN wires in steel metal conduits, and Romex cables are permitted for residential wiring, as long as all applicable National Electrical Code and local state requirements are met. In most places DIY wiring by a person who does not carry Electrician’s license is against the Code.
 

Offline james_s

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Re: Electrical wiring for Timber Frame House
« Reply #14 on: April 14, 2021, 10:29:59 pm »
Having said that, in the United States both individual THHN wires in steel metal conduits, and Romex cables are permitted for residential wiring, as long as all applicable National Electrical Code and local state requirements are met. In most places DIY wiring by a person who does not carry Electrician’s license is against the Code.

Fortunately it's perfectly legal here for a homeowner to do their own wiring, licensed or not. They still have to obtain a permit and have it inspected though, it has to follow all the same rules as it would if done by a licensed professional.
 

Offline Bud

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Re: Electrical wiring for Timber Frame House
« Reply #15 on: April 14, 2021, 10:35:38 pm »
If you want to understand how it is done in North America, download and browse a copy of National Electrical Code (NEC) or Canadian Electrical Code book.
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Offline wizard69

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Re: Electrical wiring for Timber Frame House
« Reply #16 on: April 15, 2021, 01:33:48 am »
Having said that, in the United States both individual THHN wires in steel metal conduits, and Romex cables are permitted for residential wiring, as long as all applicable National Electrical Code and local state requirements are met. In most places DIY wiring by a person who does not carry Electrician’s license is against the Code.

Fortunately it's perfectly legal here for a homeowner to do their own wiring, licensed or not. They still have to obtain a permit and have it inspected though, it has to follow all the same rules as it would if done by a licensed professional.

Even this varies a lot from region to region, that is what is required with respect to licensing and DIY work.
 

Online themadhippy

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Re: Electrical wiring for Timber Frame House
« Reply #17 on: April 15, 2021, 02:23:00 am »
Quote
If you want to understand how it is done in North America, download and browse a copy of National Electrical Code (NEC) or Canadian Electrical Code book.
And to see how the uk is supposed to do it  just shell out  70'ish quid  for the regs,then chuck in the onsite guide  and dont forget  your  guide to  the building regs,you might just get  change from £100 for those 3,but dont become to attached to them,as by the time you've  finished  reading  them they'll have issued a new amended edition
 
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Online Monkeh

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Re: Electrical wiring for Timber Frame House
« Reply #18 on: April 15, 2021, 02:45:50 am »
Quote
If you want to understand how it is done in North America, download and browse a copy of National Electrical Code (NEC) or Canadian Electrical Code book.
And to see how the uk is supposed to do it  just shell out  70'ish quid  for the regs,then chuck in the onsite guide  and dont forget  your  guide to  the building regs,you might just get  change from £100 for those 3,but dont become to attached to them,as by the time you've  finished  reading  them they'll have issued a new amended edition

Don't forget to buy the other couple of dozen standards BS7671 makes reference to, by the time you're done you might have change from three grand.
 

Offline james_s

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Re: Electrical wiring for Timber Frame House
« Reply #19 on: April 15, 2021, 05:06:27 am »
I read the original post again and it sounds like you're considering one of two different methods that I assume both pass code where you are?

Here 99% of houses are wired with Romex, a trade name for cable consisting of 2 or more conductors and a safety ground wire inside a vinyl jacket. It is run directly through holes in the wall studs with metal nail stop plates installed over the spots where it passes through the studs. Commercial buildings typically use metal conduit holding individual conductors. Occasionally you see raceways which are a type of surface mounted conduit but it is mostly for retrofit work and things like running wire along an exposed wooden beam, it was a lot more common in the past.

If I were building a house from the ground up I would seriously consider using conduit for all the wiring, it is wonderful to work with and makes it so much easier to add to or modify the system later on. It's a lot more expensive and labor intensive to install though so it's very rare in residential construction although I have seen it in condo and apartment buildings and my mother's house was previously owned by a commercial electrician and he did a lot of the wiring in that style.
 

Offline twospoons

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Re: Electrical wiring for Timber Frame House
« Reply #20 on: April 15, 2021, 09:24:31 am »
Here in NZ probably 95% of our houses use timber framing. All the wiring is pvc covered copper cable, in 2.5mm^2 copper for 10A power outlet circuits (on 15A breakers)  and 1mm^2 for lighting.  The cable is usually run through the ceiling and wall cavities without using conduit of any sort.
For reference we use  a 230V 50Hz earthed neutral system, so each cable has a phase, neutral and earth wire.
 

Offline Siwastaja

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Re: Electrical wiring for Timber Frame House
« Reply #21 on: April 15, 2021, 03:15:14 pm »
Normal PVC insulated wiring inside flexible plastic tubing. Of course using products designed and certified for this.

There is no need for special fire-proof materials, nor they are required almost anywhere AFAIK. This is because properly sized and fused wiring just simply has no mechanism to overheat and set things on fire. Note though that law requires certified professionals to do the planning and perform the installations.

The key is to understand that the distribution box fuse size defines the copper gauge, this is a simple table lookup. Larger wire area is required when the wiring is run inside thermal insulation materials.

Note that the required cross-sectional areas are quite a bit more than the classical "rules of thumb", because first, fuses are not precision devices so a 16A fused circuit can carry up to 24A pretty much indefinitely, and 32A for quite some time (an hour, maybe), and then again, a typical house wiring consists of first PVC insulation around the wires, then another 1-2 layers of PVC outer sleeve, then air gap, then the flexible cable conduit, then more or less thermally insulating building materials. And it needs to last for decades without degradation so basically the PVC has to keep below about 60 degC. This is why 2.5mm^2 is very typical even for the circuits using smallest sensible fuse sizes.
« Last Edit: April 15, 2021, 03:17:00 pm by Siwastaja »
 

Online Monkeh

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Re: Electrical wiring for Timber Frame House
« Reply #22 on: April 15, 2021, 03:35:58 pm »
Note that the required cross-sectional areas are quite a bit more than the classical "rules of thumb", because first, fuses are not precision devices so a 16A fused circuit can carry up to 24A pretty much indefinitely, and 32A for quite some time (an hour, maybe) ...This is why 2.5mm^2 is very typical even for the circuits using smallest sensible fuse sizes.

Thankfully, we don't use fuses any more, so 2xIn will trip in just a few minutes, and massively oversized conductors are not actually required or beneficial.
 

Offline Gyro

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Re: Electrical wiring for Timber Frame House
« Reply #23 on: April 15, 2021, 04:03:47 pm »
Note that the required cross-sectional areas are quite a bit more than the classical "rules of thumb", because first, fuses are not precision devices so a 16A fused circuit can carry up to 24A pretty much indefinitely, and 32A for quite some time (an hour, maybe) ...This is why 2.5mm^2 is very typical even for the circuits using smallest sensible fuse sizes.

Thankfully, we don't use fuses any more, so 2xIn will trip in just a few minutes, and massively oversized conductors are not actually required or beneficial.

I was watching a video just yesterday, where old Wylex re-wireable fuses were tested in series with modern MCBs. The old fuses blew first every time!  :o


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Online themadhippy

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Re: Electrical wiring for Timber Frame House
« Reply #24 on: April 15, 2021, 04:20:32 pm »
Quote
Thankfully, we don't use fuses any more, so 2xIn will trip in just a few minutes, and massively oversized conductors are not actually required or beneficial
who said? rewirable fuses are still fairly widespread , the current regs even  has  a correction factor for them.
 


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