Change bathroom switch to separate light and fan.

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Awrrr
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#2212876 8-Apr-2019 14:38

There's nothing to figure. Just leave the two black wires connected together on the switch.

Edited to clarify: The loop terminal on the switch just acts as a convenient way of connecting the wires to each other. The switch doesn't do anything here. As long as the black wires are connected together, it doesn't matter if they are connected to the switch.

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gregmcc

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#2212949 8-Apr-2019 15:15

I think the 1st thing to do is to have a read of

NZECP 51 2004 New Zealand Electrical Code of Practice for Homeowner Occupiers Electrical Wiring Work in Domestic Installations - Published 27 July 2004

This outlines what you can and can't legally do.

A couple of questions you should ask yourself

Are you competent?

Will you be able to isolate power effectively before you do the work?

You mentioned that there is conduit wiring.....ECP 51 only allows the home owner to work on TPS wiring.

Do you have an Inspector sorted out to complete the inspection of the homeowner work as required by ECP51? (this will more than likely cost more than simply getting an electrician to do the work)

larknz

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#2212951 8-Apr-2019 15:16

I think that a lot of uneducated assumptions are being made here. The two red wires together could be a feed in and out, with only a single wire going to the light, with the fan looped off the light.
I'm not saying this is what is happening, but you need someone who knows what they are doing to investigate properly.

Paul1977

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#2212993 8-Apr-2019 15:24

gregmcc:

Are you competent?

Will you be able to isolate power effectively before you do the work?

You mentioned that there is conduit wiring.....ECP 51 only allows the home owner to work on TPS wiring.

Do you have an Inspector sorted out to complete the inspection of the homeowner work as required by ECP51? (this will more than likely cost more than simply getting an electrician to do the work)

I'm competent to do the physical work provided I am 100% positive I understand what it is I'm doing. I wouldn't proceed if I didn't understand what I was doing

I'm not moving or relocating any conduit wiring.

You're saying changing a light switch without moving or relocating any cabling or doing any work on the switchboard requires an inspection?

EDIT: Forgot to also say, yes I can (and will) isolate the power before doing anything.

Rikkitic

Awrrr
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#2212994 8-Apr-2019 15:29

gregmcc:

I think the 1st thing to do is to have a read of

NZECP 51 2004 New Zealand Electrical Code of Practice for Homeowner Occupiers Electrical Wiring Work in Domestic Installations - Published 27 July 2004

This outlines what you can and can't legally do.

A couple of questions you should ask yourself

Are you competent?

Will you be able to isolate power effectively before you do the work?

You mentioned that there is conduit wiring.....ECP 51 only allows the home owner to work on TPS wiring.

Do you have an Inspector sorted out to complete the inspection of the homeowner work as required by ECP51? (this will more than likely cost more than simply getting an electrician to do the work)

These are all good points but ultimately it is up to the individual. As someone else here said, I am not advocating anything, just trying to answer the question. Some things shouldn't be messed with. Other things are not difficult or especially dangerous if approached with common sense.

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Paul1977

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#2212997 8-Apr-2019 15:32

larknz: I think that a lot of uneducated assumptions are being made here. The two red wires together could be a feed in and out, with only a single wire going to the light, with the fan looped off the light.
I'm not saying this is what is happening, but you need someone who knows what they are doing to investigate properly.

I'm quite sure the fan is not looped off the light and is wired from the switch, but I can easily get up in the roof space and check this - which I will do.

Because I am not an electrician I want to be sure what I am doing is safe and correct, so any assumptions would be checked and confirmed before proceeding.

If after further investigating anything is unclear, or what I want to do falls outside of what a home owner is legally allowed to do, then I simply won't proceed. Like I said earlier, it's worth doing if I can easily and legally do it myself, but not worth it if I have to pay an electrician.

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Rikkitic

Awrrr
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#2212998 8-Apr-2019 15:36

larknz: I think that a lot of uneducated assumptions are being made here. The two red wires together could be a feed in and out, with only a single wire going to the light, with the fan looped off the light.
I'm not saying this is what is happening, but you need someone who knows what they are doing to investigate properly.

If the red wires are disconnected one at a time as suggested above, it will become clear if either device is looped off the other. If it behaves as expected, the switch can be changed without problem. If it doesn't, it's time to call in the electrician. Without wanting to minimise the potential dangers of electrical DIY, I feel that sometimes there is an element of patch protection with this kind of thing. OP just wants to do a fairly straightforward switch swap. He shouldn't need an electrical engineer for that.

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gregmcc

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#2212999 8-Apr-2019 15:39

Paul1977:

larknz: I think that a lot of uneducated assumptions are being made here. The two red wires together could be a feed in and out, with only a single wire going to the light, with the fan looped off the light.
I'm not saying this is what is happening, but you need someone who knows what they are doing to investigate properly.

I'm quite sure the fan is not looped off the light and is wired from the switch, but I can easily get up in the roof space and check this - which I will do.

Because I am not an electrician I want to be sure what I am doing is safe and correct, so any assumptions would be checked and confirmed before proceeding.

If after further investigating anything is unclear, or what I want to do falls outside of what a home owner is legally allowed to do, then I simply won't proceed. Like I said earlier, it's worth doing if I can easily and legally do it myself, but not worth it if I have to pay an electrician.

It would be a good bet the the fan is looped directly off the light fitting, as an electrician putting a fan in the option would have been given at the time to the homeowner, to come on with the light or with much more cost time and materials wire it back to the light switch, but still have it come on with the light. 99% of homeowners would have chosen the cheap option.

gregmcc

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#2213002 8-Apr-2019 15:44

Rikkitic:

larknz: I think that a lot of uneducated assumptions are being made here. The two red wires together could be a feed in and out, with only a single wire going to the light, with the fan looped off the light.
I'm not saying this is what is happening, but you need someone who knows what they are doing to investigate properly.

If the red wires are disconnected one at a time as suggested above, it will become clear if either device is looped off the other. If it behaves as expected, the switch can be changed without problem. If it doesn't, it's time to call in the electrician. Without wanting to minimise the potential dangers of electrical DIY, I feel that sometimes there is an element of patch protection with this kind of thing. OP just wants to do a fairly straightforward switch swap. He shouldn't need an electrical engineer for that.

If it was a straight forward switch swap there really wouldn't be an issue here, but it seems that this is not straight forward as the OP is not 100% exactly how it is wired

BTW quite big difference between an electrician and and electrical engineer, "Electrical Engineers create designs that electricians have to fix to make work as intended"

Rikkitic

Awrrr
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#2213008 8-Apr-2019 15:51

gregmcc:

If it was a straight forward switch swap there really wouldn't be an issue here, but it seems that this is not straight forward as the OP is not 100% exactly how it is wired

BTW quite big difference between an electrician and and electrical engineer, "Electrical Engineers create designs that electricians have to fix to make work as intended"

I was being hyperbolic. 'Rocket scientist' didn't quite fit. He says in an earlier post that the fan was clearly installed later, with a separate cable. From that and the way the switch is wired, my money is on straightforward. But it is an easy test to do and then there would be no doubt.

OP sounds suitably cautious and that is good. But he doesn't seem to have a lot of confidence and that is less good. To be perfectly clear, if there is ever any doubt of any kind when playing with things that can kill you, don't. It isn't worth it.

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Paul1977

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#2213010 8-Apr-2019 15:51

gregmcc:

If it was a straight forward switch swap there really wouldn't be an issue here, but it seems that this is not straight forward as the OP is not 100% exactly how it is wired

BTW quite big difference between an electrician and and electrical engineer, "Electrical Engineers create designs that electricians have to fix to make work as intended"

Fair enough. I posted without sufficient information, as I had only looked at how the switch was wired but hadn't looked at the batten holder or the fan. I will check these so I can clarify with 100% certainty how they are wired.

EDIT: Typo.

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Paul1977

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#2213016 8-Apr-2019 16:05

Rikkitic:

gregmcc:

If it was a straight forward switch swap there really wouldn't be an issue here, but it seems that this is not straight forward as the OP is not 100% exactly how it is wired

BTW quite big difference between an electrician and and electrical engineer, "Electrical Engineers create designs that electricians have to fix to make work as intended"

I was being hyperbolic. 'Rocket scientist' didn't quite fit. He says in an earlier post that the fan was clearly installed later, with a separate cable. From that and the way the switch is wired, my money is on straightforward. But it is an easy test to do and then there would be no doubt.

OP sounds suitably cautious and that is good. But he doesn't seem to have a lot of confidence and that is less good. To be perfectly clear, if there is ever any doubt of any kind when playing with things that can kill you, don't. It isn't worth it.

I have confidence in my ability and level of workmanship, I just understandably want to be 100% sure what I'm doing is correct because... you know... electricity! That probably makes me sound less confident. Basically I know enough to know what I don't know.

I'll admit previous switches/sockets/lights I've changed have been like-for-like swaps I never gave too much thought of how they were wired - because it didn't matter. With this one it's important for me that I fully understand how the wiring works.

Rikkitic

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#2213030 8-Apr-2019 16:28

I have done a lot of my own house wiring over the years, much of it in countries with less stringent regulations. New Zealand is hyper-cautious when it comes to safety in all things and I sometimes think it is a little over the top in this regard. I would be interested to know if there are any stats on house fires and electrocutions caused by DIY-ers. The only case of electrocution I can recall was actually caused by an electrician, compounded by an inspector. This is how I remember it from media reports a few years ago. The electrician wired a hot water cylinder backwards, making the metal live, and the inspector passed it (probably without bothering to actually do the inspection). When the homeowner crawled under the house to check a leak, he was fried. I'm not sure anymore of the exact details, but that is how I recall it.

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Aredwood

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#2213270 8-Apr-2019 21:16

Rikkitic:
I have done a lot of my own house wiring over the years, much of it in countries with less stringent regulations. New Zealand is hyper-cautious when it comes to safety in all things and I sometimes think it is a little over the top in this regard. I would be interested to know if there are any stats on house fires and electrocutions caused by DIY-ers. The only case of electrocution I can recall was actually caused by an electrician, compounded by an inspector. This is how I remember it from media reports a few years ago. The electrician wired a hot water cylinder backwards, making the metal live, and the inspector passed it (probably without bothering to actually do the inspection). When the homeowner crawled under the house to check a leak, he was fried. I'm not sure anymore of the exact details, but that is how I recall it.

That case was actually the electrician wiring the incoming mains cables to the house the wrong way around. And neither the original electrician, the inspector, or the linesman who connected the power, did any of the required tests. That caused the hot water cylinder and the water pipes to become live. As the earth and neutral wires are linked together at the main switchboard.

Sure, that should never have happened. But then again, lots of plane crashes have happened due to both the pilot and copilot making mistakes. Unfortunately, it is almost impossible to stop humans from making mistakes. Please don't tar all electricians with the same brush, just because of the mistakes of a very small group.

With most DIY electrical, It is like asking “can I drive my car on the road if I dont have a valid drivers license?” The answer will almost always be No. Even though doing so would be low risk, if your license had only just expired, and you are just driving to the AA so you can get it renewed. Vs if you have never driven before, and you want to drive between Auckland and Wellington at night during wet weather.

edit to add

I do think that some of the electrical rules are over the top. But it is the Standards Committees who are at fault. As every few years, they release new, tougher versions of the codes. Which in turn makes it impossible for the tradie to do a cheap but still compliant job. This only encourages the cowboys and dodgy DIY work. (last bit is not directed at any particular person, it is a general comment out of frustration at having to give customers expensive quotes for jobs. When the quote could be alot cheaper if I was allowed to use an older version of the codes). This is a problem across all of the trades. And it makes houses more expensive.

Rikkitic

Awrrr
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#2213292 8-Apr-2019 21:45

Aredwood:

That case was actually the electrician wiring the incoming mains cables to the house the wrong way around. And neither the original electrician, the inspector, or the linesman who connected the power, did any of the required tests. That caused the hot water cylinder and the water pipes to become live. As the earth and neutral wires are linked together at the main switchboard.

Sure, that should never have happened. But then again, lots of plane crashes have happened due to both the pilot and copilot making mistakes. Unfortunately, it is almost impossible to stop humans from making mistakes. Please don't tar all electricians with the same brush, just because of the mistakes of a very small group.

With most DIY electrical, It is like asking “can I drive my car on the road if I dont have a valid drivers license?” The answer will almost always be No. Even though doing so would be low risk, if your license had only just expired, and you are just driving to the AA so you can get it renewed. Vs if you have never driven before, and you want to drive between Auckland and Wellington at night during wet weather.

edit to add

I do think that some of the electrical rules are over the top. But it is the Standards Committees who are at fault. As every few years, they release new, tougher versions of the codes. Which in turn makes it impossible for the tradie to do a cheap but still compliant job. This only encourages the cowboys and dodgy DIY work. (last bit is not directed at any particular person, it is a general comment out of frustration at having to give customers expensive quotes for jobs. When the quote could be a lot cheaper if I was allowed to use an older version of the codes). This is a problem across all of the trades. And it makes houses more expensive.

Thank you for clarifying the details. I wasn't sure of them. I agree with you that things can go wrong and all electricians should not be judged by the mistakes of a few. This was an unfortunate but exceptional case. I wasn't suggesting that all electricians are this shoddy or irresponsible. I do wonder how many people have actually died as a result of improper electrical work, whether professional or DIY, and how many fires have been caused by this. I suspect very few.

I agree that the restrictive codes are counterproductive. I know that private citizens are allowed to do almost all electrical work in their own homes in America and other places, or at least they used to be. I don't think that has resulted in coast to coast house fires or unusual numbers of electrocutions. Of course mains voltage is only 110 so the survival rate will be a little higher.

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