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personthingy
21-05-2006, 06:58 PM
Is there any LEGAL reason why a heated towel rail can not be wired on the same circuit as the hot water cylinder?

I figure that a towel rail that gets switched of at peak times is no big deal, but the cost and hassle involved in getting a new feed from the switchboard is a complete pain in the **** , so if there is no legal reasons not to hook directly onto the feed for the HWC, then thats what will be done in this case as the HWC is directly behind the ideal place for the towel rail.

Scouse
21-05-2006, 07:20 PM
Hi personthingy. Legally? Don't know but the very thought of a bit of home wiring anywhere near the damp/moist bathroom makes me cringe.

personthingy
21-05-2006, 07:27 PM
Actually, i just realized... theres the small issue of no RCD on the HWC circuit.....

What about hooking an appliance of such low wattage on to the lighting circuit?

Burnzee
21-05-2006, 07:40 PM
I too, would be worried about home wiring in a damp atmosphere. Don't know about legal reasons but common sense seems to indicate it's no on!! Pun intended!!

Firstly, are you planning on connecting the heater rail in series or in parallel. I'm worried about the current draw on the connection, switch and wiring. Reckon at the very least you will blow the fuse. The peak current when the water heater switches on will blow your lights out!!

Don't do it, get a good electrician in and do the job properly. Might cost you serious coin but it will save your house. Remember the next life you save - might be your own!!

BURNZEE

personthingy
21-05-2006, 07:44 PM
Firstly, are you planning on connecting the heater rail in series or in parallel. I'm worried about the current draw on the connection, switch and wiring. Reckon at the very least you will blow the fuse. The peak current when the water heater switches on will blow your lights out!!


BURNZEEI suspect you are not aware just how little a heated towel rail uses.... They vary, but seldom use anything more than 100watts

Greg
21-05-2006, 07:54 PM
My immediate thought, given your question, is that if you have to ask questions like that then you shouldn't be playing aroung with that kinda stuff. And hope you don't have any other family living in the house if you do.

Burnzee
21-05-2006, 08:01 PM
Yes, I'm well aware how much a heated towel rack draws. Ours takes about 60 watts. Now compare that with how much your HWC draws and you will understand my concern.

BURNZEE

personthingy
21-05-2006, 08:16 PM
Yes, I'm well aware how much a heated towel rack draws. Ours takes about 60 watts. Now compare that with how much your HWC draws and you will understand my concern.

BURNZEESo a circuit that has a 16 amp breaker, 2.5mm cable and running 3 K of HWC element (at a guess, in reality probably less) is hardly going to be overloaded by the extra 60 watts (0.25 amp) imposed on it by a towel rail.

Greg. The reason i ask is not because i don't understand what i am doing, but because i am concerned about a legal fine point, not a practical one. I can't count the places that were wired by me, over the last twenty years, have passed inspection, and are of course fine.
Last time i read the regs, things like heatlamps, fans, and stuff like that were OK to wire on lighting circuits provided they were of very low power consumption. I don't specificly remember "towel rails" being mentioned, but they do seem to be in essence the same kind of thing. I just thought i'd ask to be sure. I'm beggining to think it was a bad idea to do so.

tweak'e
21-05-2006, 08:21 PM
I'm worried about the current draw on the connection, switch and wiring. Reckon at the very least you will blow the fuse. The peak current when the water heater switches on will blow your lights out!!

BURNZEE

err....noone suggested installing the hotwater hetter on the lighting ciruit.

its not advaisable to connect another appliance to the hotwater feed simply due to its high fuse rating. if there is a short, ie through you, the fuse won't blow very quickly.

personthingy
21-05-2006, 08:33 PM
err....noone suggested installing the hotwater hetter on the lighting ciruit.

its not advaisable to connect another appliance to the hotwater feed simply due to its high fuse rating. if there is a short, ie through you, the fuse won't blow very quickly.The HWC has a 16a breaker, same as most of the plug circuits here, The lights are on 2 very underloaded 10amp circuits, that share RCD protection with most of the house.

There's also the issue that the switch for the HWC here is sensibly located behind the wood pile, so it turns out that the HWC circuit is often turned off at the switchboard instead to keep the bill down when the coalrange is going to be kept in use. thus it would be a particually bad source of power for anything else

So i assume that the lighting circuit would be the better local circuit to impose a towel rails enormous load upon, as it is RCD protected, and it is a lower rated breaker?

PaulD
21-05-2006, 09:31 PM
its not advaisable to connect another appliance to the hotwater feed simply due to its high fuse rating. if there is a short, ie through you, the fuse won't blow very quickly.

The milliamps it takes to kill you usually doesn't blow the fuse whatever rating it is hence RCDs.

Scouse
21-05-2006, 11:32 PM
and then, of course, there is the lack of home owner's insurance when the house burns down.

Murray P
21-05-2006, 11:41 PM
No.

personthingy
22-05-2006, 09:13 AM
So i take it that all of you who are full of critism but have no actual answers don't actually know the answer to the questions but are terribly and rightly scared of this electricity stuff.

{sarcasm} Thankyou for your expert advice {/sarcasm}

tweak'e
22-05-2006, 12:40 PM
So i assume that the lighting circuit would be the better local circuit to impose a towel rails enormous load upon, as it is RCD protected, and it is a lower rated breaker?

the legal side i have NO idea whatso ever.....been out of doing it way to long.
lighting ciruit is better than the HW one and if your lucky you can tap into the bathroom lightswtch, change the wall plate to double switch etc so you have an easy accible switch for the towe rail. however it may not be possible to get to a lighting ciruit so a powerpoint is best bet.


The milliamps it takes to kill you usually doesn't blow the fuse whatever rating it is hence RCDs.
true, however please trust me when i say 10 ciruit breaker can save your life ! <ouch> (rcd's are far better but not many homes have them)

Burnzee
22-05-2006, 12:44 PM
I, for one are not scared of this electrical stuff. After all, whilst not a sparky, I am a keen electronics constructor. This doesn't make me an expert in electrics or the law. But I hope with the bit of working knowledge, I do have, it does allow me a bit of common sense.

It appears to me, you posted this thread for comfort. You are unsure yourself and want us to re-assure you. Seems everyone else is telling you not to do it but you will do what you will do.

One bit of law I do know in regards to this is:
Any home wiring must be inspected and certified by a credited electrician. Otherwise you can kiss your home insurance goodbye and leave yourself wide open to the law should someone get 'cuted!!

You may not like our answers but use your common sense, spend a few buck$ and get the job done correctly.

BURNZEE

personthingy
22-05-2006, 01:05 PM
I, for one are not scared of this electrical stuff. After all, whilst not a sparky, I am a keen electronics constructor. This doesn't make me an expert in electrics or the law. But I hope with the bit of working knowledge, I do have, it does allow me a bit of common sense.

It appears to me, you posted this thread for comfort. You are unsure yourself and want us to re-assure you. Seems everyone else is telling you not to do it but you will do what you will do.

One bit of law I do know in regards to this is:
Any home wiring must be inspected and certified by a credited electrician. Otherwise you can kiss your home insurance goodbye and leave yourself wide open to the law should someone get 'cuted!!

You may not like our answers but use your common sense, spend a few buck$ and get the job done correctly.

BURNZEEBack on planet average NZ income or less, no one is going to spend the bucks when the bucks aren't there, The whole house is slowly being rewired and fixed up, and is due to be inspected anyway, but before it does we wish to get it up to standard anyway that we realisticly can while at the same time keeping it comfortable (ish) Some of the permanant wiring that was in place before i took to it was far rougher than anything that i would rig up as a temperary worklight

Your right, in so much as i don't remember specificly if heated towel rails are allowed to be on lighting circuits, but as things like clocks, fans, heatlamps, and other low draw appliances are, i am assuming that heated towel rails would be. I am making sure, or at least that was the intension. Your also right that i will do what i will do.

Also... Where's this myth that a "credited electrician" actually knows what they are doing coming from? Sorry, While i know many sparky types i respect for thier standards, i also i know too many "credited sparkys" that i wouldn't trust to change a light bulb.

Jimmy D
22-05-2006, 01:14 PM
i suggest looping it off a powerpoint if it's possible, i used to be an electrical apprentice and when we did inspections, things connected to the lighting circuit were frowned apon.
All the towel rails i've installed have been from 2.5mm power point circuits. a lot of towel rails have a switch of their own on them too but if they dont all you need to do is wire in a PCU with a switch on it.
oh and its not a good idea to connect it to the hot water, i'm unsure of the regulations but it's supposed to have its own feed and should stay that way.
hope this helps,
good luck

tweak'e
22-05-2006, 01:15 PM
Where's this myth that a "credited electrician" actually knows what they are doing coming from? Sorry, While i know many sparky types i respect for thier standards, i also i know too many "credited sparkys" that i wouldn't trust to change a light bulb.
so true. i've lost count of the amount of rip off sparky's around (and i've worked on new homes where the place was half burnt down due to sparky fault).
also locally sparky's are the 2nd highest $$$$ earners at the moment. (plumbers are no1 but then again theres 30 sparkys for every plumber......)

godfather
22-05-2006, 01:22 PM
If the lights are RCD protected, I am not aware of any part of AS/NZS 3000:2000 ("The Wiring Rules") that would prohibit the connection of a heated towel rail.

Afterall, you can connect a heat/light/fan fitting to the circuit.

BUT...

The location of the heated towel rail must be in the correct "Zone" and have the appropriate IP rating as detailed in the Standard irrespective of what it's connected to.

Murray P
22-05-2006, 01:24 PM
You're better off putting it on a lighting circuit than one that can potentially draw as much power as a HWC feed (35amps), that's why they're the only thing on that circuit. You'd also run in to trouble if your HWC is on ripple control or night rates.

Scouse
22-05-2006, 01:27 PM
Yes... ""Also... Where's this myth that a "credited electrician" actually knows what they are doing coming from? Sorry, While i know many sparky types i respect for thier standards, i also i know too many "credited sparkys" that i wouldn't trust to change a light bulb."" But it is the Electrical Certificate of Compliance issued by the said sparky, complete with number, job description his name, his registration number, etc., which the insurance company will be looking to trace if there is the slightest suggestion that a fire has an electrical cause. I don't care if he really knows his stuff. As long as he has a registration number on my certificate.

personthingy
22-05-2006, 01:33 PM
If the lights are RCD protected, I am not aware of any part of AS/NZS 3000:2000 ("The Wiring Rules") that would prohibit the connection of a heated towel rail.

Afterall, you can connect a heat/light/fan fitting to the circuit.

BUT...

The location of the heated towel rail must be in the correct "Zone" and have the appropriate IP rating as detailed in the Standard irrespective of what it's connected to. Thankyou godfather.
Its a good metre and a half from the bath on the oppisite wall. All plug and lighting circuits are indeed RCD protected.

Winston001
22-05-2006, 01:35 PM
I'm no sparky - got a cupboard lightswitch wired to a 3 point plug presently. :D

But isn't there a powerpoint circuit close by? I'm having trouble imagining a house where there is lighting wiring but no convenient powerpoint feed in the same general area. That's what I've always assumed was used for towel rails.

personthingy
22-05-2006, 01:51 PM
I don't care if he really knows his stuff. As long as he has a registration number on my certificate.All i'll say is that i don't think we are from the same planet. On mine what matters is a job well done, safely and all that good stuff. Cert numbers don't mean **** when someones sloppy work just cost someone you love their life, allthough they will help with insurance which i couldn't give a toss about.

Yes i understand that certification is there to protect us from sloppy jobs done by cowboys, (many of whom are registered sparkys.) I also understand that at the end of the day the system is far from perfect, and as a result of that i would rather trust someone i knew knew their stuff than someone with a bit of paper to say they have done the course or what ever, and now i am talking about far more than the registration of sparkies, but just about every field that requires qualification.

Scouse
22-05-2006, 02:10 PM
""I also understand that at the end of the day the system is far from perfect, and as a result of that i would rather trust someone i knew knew their stuff than someone with a bit of paper to say they have done the course or what ever."" Just out of interest.... How would you know?

personthingy
22-05-2006, 02:23 PM
In answer to your question Scouse,

Worklike attitude vs "want to get out of here and get paid" or other not give a damn attitude

Reputation.

Common sense.

Testing knowledge (where i do know something about the field) and unlike an educational institution, i want to see if they have thought about what they are doing as opposed to checking to see if they can regurgitate what was just "taught".

I've known too many sparkys who are more interested in the lunchtime joint and getting paid than making 100% sure everything they do is as safe as it can or even should be. I've even worked with sparkys who got me to check the regs for them so they can decide if they should certify some of my equipment i got them to check. I'd work with those sort for paperwork reasons, but i wouldn't get them to install a lightbulb. (see previous comments)

Fortunately i don't have to work near such bozos these days, they wouldn't last a week in my field of work, but it scares me that they go on to work for reputable companies actually installing stuff.

SurferJoe46
22-05-2006, 02:31 PM
Here in the US where we have really tough laws, and I imagine NZ has some if not all of the same stuff.

A hot water heater must have a dedicated circuit for itself. This is the same for any high amp devices.

We also have to install GFCI's (Ground Fault Circuit Interrupt) in any area that has the potential for a short to ground from an ungrounded appliance or early design...pre 1980 I think or so.

A GFCI will kill a circuit feed if there's even a very small loss of ground potential or interruption. I don't think you could electrocute yourself intentionally with one of these in the circuit no matter how hard you try.

Most all newer appliances have double insulation or isolation to the outer case or skin of the device...this consists of a non-conductive case or cover like the outside of a power drill or toaster or portable device. These do not need a third wire to lead to ground if they pass the UL isolation test process.

One GFCI can cover any circuit that passes thru it to other circuits up to the rated value of the wire. The ability to open the circuit is almost instantaneous as the GFCI is powered by the line that goes thru it, so it's constantly monitoring the line/ground parameters. These can be in the form of a single wall plug, or even installed at the power distribution panel (fuse box or circuit breaker panel).

Then there's also torte law....that says that if you cause your domicile to be damaged or destroyed because you broke a building code, a law or the "spirit of the law", then your insurance company has legal grounds to walk off of the claim and not pay you for the loss.

Seems to me, that under those circumstances, I'd pull another leg off the panel and heat your towels with a new circuit or just get your butler/maid to sit on them for a while to warm them up.

godfather
22-05-2006, 04:19 PM
Not much different here Joe.

What you call a GFCI we call an RCD (Residual Current Device).
If the (illegal) wiring caused a fault, the insurance will walk away.

Hot Water circuits are usually a separate circuit, due to historical (or future) tariff considerations where the water heater can be on a controlled or "night only" rate.

Plus there is a severe range of regulatory penalties (not frequently invoked though) for non compliant work. They are much tougher on hunting down the Tradesmen than on the general public, as far as "policing" the matter of integrity of work, to the extent that some in the trade have given up to do other things.

"Double Insulation" also applies here.

Neil McC
22-05-2006, 06:44 PM
OK I'll stick my neck out!! No legal reason not to come off the H/W circuit, as long as the feed to the towel rail is the same size cable as the H/W feed.Then the circuit itself is still protected by the fuse, which is there to protect the cable. It would be better to come off the light circuit if you can.And a permanently wired appliance doesn't have to be on an RCD.I've actually had some towel rails trip an RCD, so had to feed them off a heater circuit in the bathroom.
As to the home owner doing any wiring, no one is allowed into a switch board. And all home owner work has to be checked and certified by a registered inspector, not electrician. I can't certify any one elses work, only my own.
And if you don't get it checked and certified, the insurance company mightn't pay out in case of fire.

SurferJoe46
23-05-2006, 04:15 AM
OK I'll stick my neck out!! No legal reason not to come off the H/W circuit, as long as the feed to the towel rail is the same size cable as the H/W feed.Then the circuit itself is still protected by the fuse, which is there to protect the cable. It would be better to come off the light circuit if you can.And a permanently wired appliance doesn't have to be on an RCD.I've actually had some towel rails trip an RCD, so had to feed them off a heater circuit in the bathroom.
As to the home owner doing any wiring, no one is allowed into a switch board. And all home owner work has to be checked and certified by a registered inspector, not electrician. I can't certify any one elses work, only my own.
And if you don't get it checked and certified, the insurance company mightn't pay out in case of fire.

I don't feel using the hot water heater feed as service for the towel heater is a good idea.

Just for giggles, assume that each leg of the heater is fused at 30 amps, then the towel heater will also work with that value too....and a 30 amps fuse for a device that pulls maybe 1 or 2 amps is not going to be a good idea.

Do you understand how bad of a short the towel heater would have to have to trip a 30 amp fuse? Does thermonuclear meltdown ring a bell?

Not safe at all.....in fact very dangerous. :(

And as far as the idea that the fuse is just to protect the in-wall wiring, although it's a good idea to not be able to see the wires glowing thru the walls, is to protect the consummable (human) who uses a device that is on the terminal end.

Houses can be replaced, humans on the other hand require lots of paperwork by the coroner, police and courts when they expire, especially from bad wiring and do-it-yourself'er installations. :annoyed:

Neil McC
23-05-2006, 09:17 AM
Just for giggles, assume that each leg of the heater is fused at 30 amps, then the towel heater will also work with that value too....and a 30 amps fuse for a device that pulls maybe 1 or 2 amps is not going to be a good idea.Do you understand how bad of a short the towel heater would have to have to trip a 30 amp fuse? Does thermonuclear meltdown ring a bell?
Not safe at all.....in fact very dangerous.

Ok, another way to look at it.Our stove circuits are fused/circuit breakered at 30 amps, and a lot of stoves now on the market don't have any fuses in them, relying on the main fuse.You can plug your shaver into the ppt on the stove.........Powerpoint circuits are fused at 20 amps, my phone charger doesn't take that.And most home hot water circuits are 16 amp here. So we fuse according to the current ratings of cable, not what is going to be plugged in.
And all new light/powerpoint circuits from a switchboard have to have an RCD fitted.It doesn't stop you getting a belt ,but is safer!!

PaulD
23-05-2006, 09:22 AM
Not safe at all.....in fact very dangerous. :(

And as far as the idea that the fuse is just to protect the in-wall wiring, although it's a good idea to not be able to see the wires glowing thru the walls, is to protect the consummable (human) who uses a device that is on the terminal end.



The lack of an RCD (or GFCI) would be a valid concern. As I mentioned before currents of 1mA can be fatal in some circumstances. A typical human could draw 230mA from a 230v contact. A typical RCD will trip on 30mA, RCDs in medical use trip at 10mA but Fuse values start around 5 Amps. Fusing can only be for the cables.

SurferJoe46
23-05-2006, 09:48 AM
Well...NO!...Not really!

The wire is designed to carry the current to the device at hand, and the fuse/breaker is set at approximately 105-110% PEP of the device in question for surge capacity.

The draw of the device must be calculated into the equation...I run wiring for a living and on a typical electric stove run, I am allowed to use 8ga copper, 4-conductor + ground for distances under 75 feet. Over that distance, I have to increase the size of the wire...in this case to 6ga or better, the same number of conductors.

Now, if you have a duplex receptical on the stove front to plug in a mixer or some other tool, it HAS TO BE seperately fused to the max allowable current that 99% of such devices should attain. Most draw an amp or two (we use 110v AC for our stuff here, 220v or 208v for our heavier equiptment). So, we typically use a 15 amp/110v receptical, although 20amp/110v units are available.

The GFCI (required on installations after a certain date) must protect the auxillary device, not the stove.

So, here I have a stove on 220v AC that draws 50 amps per leg thru #8ga copper multi-strand cable, 4-conductor (2 legs of 110v, 2 matching ground legs, and 1 aux ground wire...all of the same gauge), for a distance of less than 75 feet. If I have a duplex receptical on the stove front (actually unheard of here in the US nowadays because of the differential draw on the legs from the 220v side), it should be seperately fused for the anticipated draw.

I was wondering why you had so many thoughts on the feasability/advisability of the installation you want...now I see. It ain't a good idea to break a 220v circuit and saddle it also with a 110v tap on one leg or the other. It will unbalance the whole circuit. But that's US law..we don't typically use 220v as our primary current.

Feeling that you should not put the towel heater on the same circuit as the water heater is still my thought for various reasons...the rule youse guys have about night current or whatever that is; the fact that you have a very minimal draw from that towel heater on a circuit designed to trip off at much higher rates; the possibility that I may misunderstand that you do or don't have GFCIs on your water heaters.

If you have a device that draws 50 amps and you are rated at 30 amps in the wiring, and the breaker is set at 50 amps, them there's a serious mis-balance.

Protection must consider all the parts of the system. You can over-rate the wire by using larger diameter, the fuse/breaker is not there to protect the wire...but the device on the end of the wire. Wiring protection is secondary...the wire itself must be up to the draw of the stove or water heater plus a fudge factor of about 10% in this case.

I am not trying to quote NZ electrical codes, just some common sense...electricity is still electricity even if you are upside down in NZ and drive on the wrong side of the road.

personthingy
23-05-2006, 10:07 AM
SurferJoe,

NZ systems are a tad different to American systems in so much as almost all domestic installations use a single phase 230volt supply for the whole house. Phase, the hot wire is fused in some way. Nuetral, the return wire is not fused, and is grounded at various points as well. We therefore do not usually have fuses on each leg of the supply for a stove or HWC. There are some houses with a 2 or 3 phase supply, but this is more usually found in industrial installations.

It's a little different from your 110 - 0 - 110 volt system where one has 2 opposing hot wires allowing 220volts supplies for heavy draw appliances such as water heating, ovens, aircon, etc, and 110v supplies for your lighter domestic lights and appliances

Hot water supplies are usually set up with a 20amp circuit breaker, or less, which is the same as how our plug circuits are set up, apart from the HWC being controlled externally by the power companys to keep peak demand slightly under control.



Back to the towel rail.....

Its going to be added to the underloaded lighting circuit, and share a few lights with a 10 amp breaker. Hopefully it doesn't trip the house RCD, if it does it's gone.

Graham L
23-05-2006, 02:26 PM
... Protection must consider all the parts of the system. You can over-rate the wire by using larger diameter, the fuse/breaker is not there to protect the wire...but the device on the end of the wire. Wiring protection is secondary...the wire itself must be up to the draw of the stove or water heater plus a fudge factor of about 10% in this case.

Taurine excreta, Joe. The fuse or breaker is there to protect the fixed wiring (and thus the whole house from fire). It can't protect the "device on the end of the wire". If the protection device is needed, it's all over for the device; that's why the excess current has happened.


... Firstly, are you planning on connecting the heater rail in series or in parallel. I'm worried about the current draw on the connection, switch and wiring. Reckon at the very least you will blow the fuse. The peak current when the water heater switches on will blow your lights out!! ... Words (almost) fail me.

Connecting a towel rail (about 60W) in series with a WHC element(2-3 KW) would not produce any surges, let alone huge ones. (Their turn on current would be just about the same as the running current: they don't get hot enough for their resistance to vary significantly. The total current would be just under 60W.

Connecting in parallel, as is normal in electrical wiring, the total load would change from 2-3 KW to (2-3 KW + 60 W). Not enough difference to bother fuses or circuit breakers which would require 2X the rated current to operate immediately. Again, there would be no surges.

Burnzee
23-05-2006, 02:53 PM
Absolutely correct, Graham L.

Unfortunately this sentence did not convey what I was thinking. What I was worried about if someone, maybe himself was to get electrocuted by faulty wiring in a damp atmosphere then the HWC fuse would not protect him. The reference to series or parallel wiring was to see if he knew the difference. If he doesn't, do you still think he should do the wiring himself?

The reference to "blowing your lights out" had nothing to do with the lighting circuit, rather I meant it could possibly kill him.

Hope this clarifies the issue.

BURNZEE

Terry Porritt
23-05-2006, 03:03 PM
If a fuse has a rating of about 5mA, then it may offer some protection.

personthingy
23-05-2006, 04:06 PM
The reference to series or parallel wiring was to see if he knew the difference. If he doesn't, do you still think he should do the wiring himself?The reference to wiring a towel rail in series with the HWC was so of the wall that "he" didn't consider it worth humoring with acknowledgment.

Burnzee
24-05-2006, 02:36 AM
Talkin' to a Building Technology Consultant today, (how's that for a BS title!!) and I put your question to him. As I recall, your question was if you could LEGALLY wire in your towel rail. Anyway, he put me onto the relevant law and website where it can be viewed. Thought it might be handy so here they are:

The Law is New Zealand Electrical Code Of Practice 51 (2004), it can be viewed here (http://http://www.ess.govt.nz/rules/rules_codes.asp) They also have a short brochure called DOING YOUR OWN ELECTRICAL WORK SAFELY AND LEGALLY (2004) which can be viewed here (http://www.ess.govt.nz/safety/pdf/brochure.pdf)

NZECP 50 may also be relevant. Hope this helps.

BURNZEE