Wiring multiple baseboard heaters

[chrisale]

Hi all,

I'm quite confident wiring some baseboards that I need to install... they're 240V, various sizes.

What I'm not sure of is how to have multiple baseboards on the same circuit? Can I do it with a 2-conductor wire (as both conductors are "hot")?

I've been scouring the net looking for a diagram of the circuit from... say... breaker-->baseboard#1-->baseboard#2-->baseboard#3

I assume also that multiple thermostats could be wired in before each heater to control that specific heater independantly from others on the circuit.. (or alternatively have one thermostat at the beginning of the circuit that would then limit all heaters on the circuit.

Any help greatly appreciated!!

Sincerely,

Chris

[Pat]

I'm not an electrician, just a home owner with electric heat.

I believe the correct thing to do is to wire them in series with 1 thermostat.

-------------heater-----------heater

-------------heater| power ===== therm |

-----------------------------------------------------------------|

not

------------------ -------------------

---------- power heater heater heater -------------------- -------------------

----------

but I am sure smarter pe> Hi all,

[barry]

If they have provision for ground connection (like, to enable tripping breaker if a short) or the mfg makes any mention of such, or if it's possible and your inspector wants it, I'd sure run 3-wire. Inspector trumps all. Hell, I'd run ground wire on principle.

All devices (thermostats, breakers, wires, heaters) must be run within rated limits at all times, meaning for wiring carrying all the load (before branching) and breakers allowed limit is 80% of breaker rating.

You want to map out the circuit much more clearly, noting all load ratings, carefully. Note mfg's requirements for heaters and see to them. Ensure that all wiring segments will be within 80% of rating for worst case and ensure that all wiring meets NEC requirements. Stuff like wire gauge, breaker rating, workmanship.

Sure, you can connect in parallel, series-connected thermostats and heaters.

Heaters can put some serious sustained stress on wiring and connections, so I'd suggest getting some professional advice beforehand, and inspection before powering it up. No disrespect intended, but your question triggers alarms.

Besides, unless you've got your own power-station, resistive electric heaters are about the most wasteful way to heat a house.

HTH, J

[Fred Wilson]

[Toller]

It is easy enough to wire, but bear in mind that the breaker and all the associated wire must be large enough to carry the current required by three heaters. Unless they are tiny, that is a problem.

My cottage had three 15a baseboards with #12 wire and a 50a breaker. It also had a 23a water heater on #12 with a 30a breaker. Amazing it didn't burn down in the 35 years it was like that.

[RBM]

You have to calculate the total load you want on each circuit, then use cables large enough to carry that load. Typically you would run the feed from the breaker box to a wall thermostat location, daisy chain the feed to another wall thermostat location, on and on until you've use up the capacity of the feed. From each wall thermostat location you would run the cables to the heaters controlled by those thermostats

[terry]

Care to expand on that? Electric heaters turn all the the electricity they consume into heat. So it then comes down to how much does electricity the cost in comparsion to other 'fuels'. We have used electric baseboards for the last 36 years. Maintenance costs have been virtually nil; no heaters have burnt out or needed replacement. Whereas if we had used fuel oil, or propane etc. there would have been furnace repairs, chimney flue cleaning etc. So just curious as to why baseboard heaters are 'wasteful'? Terry

[chrisale]

Hi all,

Thank you very much for your responses.

No disrespect taken... I appreciate all your help and your sound advice. I'll give you some more details on what I've got going so far. Hopefully that will both allow you to help me out a little more and ease any concerns. :)

I have a large supply of standard 12/2 wiring with bare ground (so max

20A, 16A being "common sense") ... which is why I asked. If required I would certainly purchase 3 conductor if I have to, but the cost of copper these days is so prohibitive, I was hoping to use what I have on hand.

Apparently the new electrical code coming into force (at least here in BC, Canada) actually allows 100% load on the wire, that said, every professional I have talked to is still abiding by the 80% rule, which just seems like good common sense to me. So that's what I'll do.

I'm just trying to plan out my circuits before I start seriously feeding wire.... so here are two examples, is something like this doable?

Circuit #1: Living Room: 2500W - room stat Bathroom #1: 500W - stat-on-heater Bathroom #2: 500W - stat-on-heater

3500W = 14.5A (240V) or 15.9A (220V)

Circuit #2: Dining Room: 1500W room stat Kitchen: 1000W room stat Bedroom: 1000W - room stat

3500W = 14.5A (240V) or 15.9A (220V)

Those loads should keep me in an acceptable range... obviously below code.

My question centers more around actual wiring. Is there any benefit in terms of load sharing / wear to series vs. parallel?

Do I use the connections on both ends of the heaters (they have identical connections on both ends for convenience) to "pass through", or simply connect them through wirenuts on the same end.

And as for the question of efficiency, we looked at all the options when replacing our oil furnace and baseboard was the only realistic and affordable option for us. (heat-pump, retrofit too expensive... gas, price too volatile + retrofit... radiant floor -- inappropriate softwood flooring) Also, considering 100% of the energy you put into an electric baseboard gets turned into heat, it's actually *more* effecient than oil, gas, or wood furnaces in terms of energy use. The actual effective heat you get out of it comes down to the efficiency of your house as a whole, which affects all heating systems equally.

Baseboard gives us both ease of installation/expansion, cheap long-term energy (BC has cheapest power in North America), virtually nil maintenance costs, and flexibility to turn off unused portions of the house.

[Jeff]

I guess it depends on if your costs for electricity is cheaper than cost of gas it would be cheaper for electric, we have a 85% efficiency furnace, uses pvc pipe for chimney and outside air intake, so i would say that most of the gas (propane) is being turned into heat. our electrical costs here are not as bad as they neighboring state but still cost prohibitive to run all baseboard heating for main source of heating. i imagine that 80% of wire load with all units connectd in series works, cant see why you would put individual thermostats on heaters in the same room though. Different rooms to create custom heating zones seems almost a no-brainer if you got the hardware.

[RBM]

You never put the baseboard units in series, always in parallel. and the heaters have wiring boxes on both ends just so you have a choice where to run the feed. You leave one end wire nutted together. If you are connecting more than one heater together, run both feed in and feed out cables into one junction box on the heater and parallel them along with the heater conductors, then jump to the next heater. Also, there would be absolutely no reason to run three conductor cable, 12/2 gives you 240 volts + ground, which is all you need

[chrisale]

excellent that is exactly what i needed to know

thanks!

Chris

RBM (remove this) wrote:

[hallerb]

Whats the OPs cost per KWH?

Around here its about a dime costs a fortune to heat with electric.

[Edwin Pawlowski]

Wish I could pay a dime. Her in CT, it is about 16¢

[chrisale]

As of my current bill, BC Hydro (it's a government-owned company) the residential rate is: $0.06330 /kW.h ... and that's after a rate hike of I think 5% last year.

so 6.3c "Canadian"... not sure if exchange rates make that much of a difference when you're talk> > Whats the OPs cost per KWH?

[Chris Lewis]

According to [e-mail] :

To be precise: the new electrical code permits 100% load on the wire, but still only 80% on the breaker. This is ONLY for electric heaters.

As an example: now you can put a 15A heater on 14ga feed with a 20A breaker. Previously it had to be 12ga.

Your combinations look pretty reasonable.

Electrically, you never connect devices in series - meaning, that the current has to flow thru more than one device to complete a circuit.

You can't use both for passthrough. The electrical connections are made at one end, the pair of wires at the other end are simply wirenutted together.

For the most part, gas and oil are cheaper than electric heat. While electric heat is 100% efficient at converting the power that gets _to_them_ to heat, that's only part of the story - the other part is efficiency at point of generation and transmission losses. You'd probably find that a modern high efficiency gas furnace likely to be more efficient than a gas powered generating station in terms of delivering watts to your door.

However, BC is largely hydro-power, but that has its own drawbacks.

BC also has a rather more moderate heating season than many parts of the US, let alone the rest of Canada.

[Mark Lloyd]

You didn't consider where that electricity comes from, and how it gets from there to your heaters..

[John Gilmer]

As others have stated, if the wire size (and thermostat capacity) sufficient for the total load there isn't a problem. Two wire (plus ground) can and is normally used.

Check the installation instructions for the baseboard heaters. They may tell you EXACTLY how to wire several heaters in "multiple." Among other "got yas" is the insulation temperature ratings of the wire. But, for example, the instructions will tell you whether the heater housing is considered a conduit for wiring purposes or do you have to run the wires for the several units in the wall or below the floor.

Pays to read and understand the installtion instruction before you buy the heaters.

[Pat]

I think with the exchange rate you get 93 volts of 52 cycle power -- but if you take it into the states with you, you can get a refund of the VAT if you keep your receipt.