Hello everyone
First of all:
We have the inspector's permission to install the cables, and that was the question that concerns us and is currently unresolved!
I am an electrician/electronics technician, but I come from the industrial sector. Therefore, I am not familiar with the relevant residential building regulations. The inspector is sick and unreachable, but time is pressing...
House wiring (new construction / prefabricated construction / timber frame).
What is currently considered the "state of the art"? We plan to separate the outlets and lighting circuits.
Supply line for outlets: NYM 2.5mm² (5 AWG). For larger rooms, is it more practical to have two branch circuits, for example in a living room with about 10 outlets?
And generally, is it allowed to connect all 10 outlets in parallel on one supply line, or is a distribution box required on site? We want to avoid a distribution box if possible.
Background: we want to install the cables over Christmas and the days following. The inspector is currently sick and unreachable...
We have the inspector's permission to lay the cables, and this is the question that worries us and is still open!
As mentioned, I am an electrician/electronics technician from the industrial sector, so the applicable standards in house wiring are unfamiliar to me.
Good luck
dettec61
First of all:
We have the inspector's permission to install the cables, and that was the question that concerns us and is currently unresolved!
I am an electrician/electronics technician, but I come from the industrial sector. Therefore, I am not familiar with the relevant residential building regulations. The inspector is sick and unreachable, but time is pressing...
House wiring (new construction / prefabricated construction / timber frame).
What is currently considered the "state of the art"? We plan to separate the outlets and lighting circuits.
Supply line for outlets: NYM 2.5mm² (5 AWG). For larger rooms, is it more practical to have two branch circuits, for example in a living room with about 10 outlets?
And generally, is it allowed to connect all 10 outlets in parallel on one supply line, or is a distribution box required on site? We want to avoid a distribution box if possible.
Background: we want to install the cables over Christmas and the days following. The inspector is currently sick and unreachable...
We have the inspector's permission to lay the cables, and this is the question that worries us and is still open!
As mentioned, I am an electrician/electronics technician from the industrial sector, so the applicable standards in house wiring are unfamiliar to me.
Good luck
dettec61
X
xMisterDx25 Dec 2022 10:36The device boxes, meaning the outlets for appliances over 2kW where it’s certain that they need to carry up to 16A for extended periods, were all installed with 2.5mm² (approximately 14 AWG) wiring in my case.
There seems to be some truth to these recommendations.
Also, you should not protect two loaded conductors carrying 15.5A with a 16A breaker.
But RotorMotor thinks they know everything better anyway, and my electrician probably just wanted to get rid of the 2.5mm² (approximately 14 AWG) wire before it started to rust 😉 or mold?
There seems to be some truth to these recommendations.
Also, you should not protect two loaded conductors carrying 15.5A with a 16A breaker.
But RotorMotor thinks they know everything better anyway, and my electrician probably just wanted to get rid of the 2.5mm² (approximately 14 AWG) wire before it started to rust 😉 or mold?
xMisterDx schrieb:
…
But RotorMotor thinks he knows everything anyway, and my electrician probably just needed to get rid of 2.5mm2 (0.0039 in²) cable before it starts to rust 😉 or mold?Fortunately, our electrician didn't need to get rid of any unnecessary 2.5mm2 (0.0039 in²) cable ;-)That's why we have slim 5x1.5mm2 (0.0023 in²) cables everywhere except in the kitchen
In my house, all the wiring is done with 2.5mm² cables, protected by a 16A circuit breaker, and the earth conductor to the garage uses 5x16mm². No 1.5mm² cables were installed anywhere, not even for the lighting. There was never any request for that; the electrician always does it this way. It wasn’t expensive either.
Well, the "new" standard states that for thermally insulated timber stud walls or ceilings, only 13A is permitted with 1.5mm² conductors.
When cables are installed concealed in plaster and/or in conduit, 16A is still allowed, provided the cable length does not exceed (I believe) 16m (52.5 feet).
That’s the theory for now. There have been reports of apartment fires across Germany when the standard was reduced from 16A to 13A because the cables suddenly were no longer considered "adequate" 😉
Personally, I prefer using 5x2.5mm² and 4-6mm² conductors (depending on the cable length to the kitchen) in a house. In addition, every room should have its own RCD (residual current device), not just the minimum two as required by the standard. Fire protection switches are also worth considering if you have a bit of extra budget for electrical installations 😉
There is so much margin built into these standards and formulas that 1.5mm² conductors can handle more than 16A (the actual issue is more likely the sockets, for example).
When cables are installed concealed in plaster and/or in conduit, 16A is still allowed, provided the cable length does not exceed (I believe) 16m (52.5 feet).
That’s the theory for now. There have been reports of apartment fires across Germany when the standard was reduced from 16A to 13A because the cables suddenly were no longer considered "adequate" 😉
Personally, I prefer using 5x2.5mm² and 4-6mm² conductors (depending on the cable length to the kitchen) in a house. In addition, every room should have its own RCD (residual current device), not just the minimum two as required by the standard. Fire protection switches are also worth considering if you have a bit of extra budget for electrical installations 😉
There is so much margin built into these standards and formulas that 1.5mm² conductors can handle more than 16A (the actual issue is more likely the sockets, for example).
xMisterDx schrieb:
The classic case. Industrial electricians who think, "I can handle laying a few cables myself," only to quickly realize, "Uh, what do I need to consider? And how do I even do this?"
Better to leave it and wait for the master electrician. Otherwise, you’ll probably end up ripping everything out again.
A quick look in the reference tables confirms it. In insulated walls, when routed inside conduit, a 3x1.5 mm² (3x16 AWG) NYM cable is only rated for 13 A, so it should be protected with a 10 A breaker. And then there’s the derating factor to consider because in mid-summer, the temperature inside the wall can easily exceed 30°C (86°F).Well, the “classic case” has already wired several houses, and they have been accepted without issues. The last one was 5 to 7 years ago, and this is the first timber frame construction with insulation. As you can see, I already suspected that things could be borderline different here. And again: we cannot just wait for the master electrician. Work has to continue. There’s probably no need to rip out the wiring, just maybe use a breaker with a lower rating.
What is strange, though, is that the homebuilder supplied everything in 1.5 mm² (16 AWG) cable, and there isn’t a single 10 A or 13 A circuit breaker included.
There is also a bit of 2.5 mm² (14 AWG) cable provided for the kitchen installation, by the way.
dettec61 schrieb:
...The strange thing is that the house construction company supplied everything in 1.5mm² (1.5 sq mm) wiring, and there wasn’t a single 10/13A circuit breaker included.
There is also a small amount of 2.5mm² (2.5 sq mm) wiring for the kitchen installation, by the way. As some comments have shown, there is nothing unusual about supplying 1.5mm² (1.5 sq mm) wiring. I suspect this is actually the majority practice. 1.5mm² (1.5 sq mm) wiring is used for sockets, and 2.5mm² (2.5 sq mm) wiring for kitchen appliances such as stove, oven, refrigerator, etc.
Similar topics