Why No Neutral for Baseboard Heater?


  #1  
Old 02-17-07, 11:40 AM
M
Member
Thread Starter
Join Date: Jun 2001
Location: Pennsylvania
Posts: 247
Upvotes: 0
Received 0 Upvotes on 0 Posts
Why No Neutral for Baseboard Heater?

I will be relocating an electric baseboard heater within the same room. During my investigation I see that it's a 240V heater (2000 watts, 8.4A) run off a dual-pole 20A breaker. No red wire in the line; white and black are separately connected to the dual-pole breaker. Run includes a ground. Question: why does this appliance not need a neutral?

Thanks.

A side question: the heater seems to be made by Interthern. I can find very little about this on the Internet. If anyone can suggest more efficient heater, please let me know.
 
  #2  
Old 02-17-07, 11:46 AM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Upvotes: 0
Received 1 Upvote on 1 Post
Wink

For or lets say to make 220V to a unit you only need the the 2 hot legs each 110V.
 
  #3  
Old 02-17-07, 12:17 PM
nap's Avatar
nap
nap is offline
New Member
Join Date: May 2006
Location: north
Posts: 4,162
Upvotes: 0
Received 1 Upvote on 1 Post
Ed is a man of few words but I, as king of verbosity of these here forums, would like to expand a bit.

In a residential electrical system, you have 2 hot legs, a neutral, and a ground (EGC)

if you utilize either of the two hot legs and the neutral, you will have 120 volts. If you utilize both of the hot legs you will have 240 volts. Now there is a 3rd situation where you utilize both hot legs and the neutral. This is a 120/240 volt circuit and provides both 120 volts (1 hot and the neutral) and 240 volts (both hot legs). It is used where the appliance connected requires both voltages for operation. Typicall an electric oven and a dryer or the 2 in a house that do utilze this type of circuit.

Straight 240 volt equipment does not require a neutral because they do not need the 120 volts provided by a 120/240 volt circuit.

The grround is a safety requirement and all current installations (without getting into too large of an expose`)is required for all circuits and shall be connected to just about anything metal in an appliance.
 
  #4  
Old 02-17-07, 12:39 PM
M
Member
Thread Starter
Join Date: Jun 2001
Location: Pennsylvania
Posts: 247
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for the quick responses, but I'm still a bit confused. All of the lights and outlets I've worked on have a neutral, typically the white wire, that "returns" to the source. This is the aspect that's confusing to me. In the wiring for the baseboard heater, there is no return. Does this make sense?

Thanks again.
 
  #5  
Old 02-17-07, 01:04 PM
nap's Avatar
nap
nap is offline
New Member
Join Date: May 2006
Location: north
Posts: 4,162
Upvotes: 0
Received 1 Upvote on 1 Post
a neutral is not truly a return. It is merely the other wire needed to complete the circuit.

getting away from resi situations a bit her but it helpd me explain.

a transformer is merely a winding of wire positioned near another winding of wire.The EMF from the energized winding induces voltage into the second set of windings.

you connect to the ends of the windings to recieve you voltage and current.

The voltage is determined by the ratio of the number of windings of one side (primary) to the other side (secondary)

simple calculation. primary has 500 wraps of wire, secondary has 250 wraps of wire.

result- primary voltage will be reduced in half.

Now if you attach a lead to the middle of the secondary (250 wraps) so that you effectively ustilize only 125 wraps of wire, you have in effect made a 4 to one reducing transformer rather than a 2 to 1 (first math situation) so you now have 1/4 of the original voltage.

This is where the neutral comes in. It is the 1/2 point in the secomndary windings of the transformer that feeds your house. You end up with 2 ways to recieve 120 volts and 1 to recieve 240 volts.

Now, what happens with a resi power system is that the neutral (or mid point tap)is grounded. This gives the unknowing the belief it is not a hot wire. If you were to remove the ground connection, you would have the exact same voltage as when it is attached. It is merely another hot wire that you ground for safety purposes (plus some other reasons but that gets into another long post)

The ground attachment allows a safety measure to be added to the whole install.

A simple situation that many unkowing may see as odd. I installed a 3 phase transformer yesterday. On the secondary side, I intentionally connected one of the legs directly to ground (as well as using it as a hot leg). This is contrary to what most non-electricians would think is correct and safe.

It casuses no problem to attach one leg of a power source to ground. It is,, inmost cases, required.

When you have a problem is when a second leg or phase becomes grounded. It;s not the fact that the second legl or phase becomes grounded actually but by being grounded, it becomes in direct connection with another leg or phase. That is where you get your flashed and bangs and sparks and fires.

Confused? I'll try to restate if so and make it more easily understood.
 

Last edited by nap; 02-18-07 at 08:24 AM.
  #6  
Old 02-17-07, 02:03 PM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Upvotes: 0
Received 1 Upvote on 1 Post
Wink

Look out nap With that much know how. Next you will have him climbing the pole to check the POT
 
  #7  
Old 02-17-07, 03:33 PM
M
Member
Thread Starter
Join Date: Jun 2001
Location: Pennsylvania
Posts: 247
Upvotes: 0
Received 0 Upvotes on 0 Posts
Nap:
Thank you for your reply.

If I could, let me present an example:
A standard outlet with a lamp plugged into it. The lamp has a 60 watt bulb. Will the "circuit" (lamp) draw only 60 watts, and the neutral will have a voltage of zero? What is the current on the hot wire leading into the outlet?

I do appreciate your time and information. My wife tells me that I'm too curious for my own good. But I'm not curious enough to climb the pole and check out the POT, whatever that is.
 
  #8  
Old 02-17-07, 05:43 PM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Upvotes: 0
Received 1 Upvote on 1 Post
Wink

Just the one leg you will read 110V to ground.

The pot on the pole is that big transformer up there . That you see all the time
 
  #9  
Old 02-17-07, 06:39 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 10,237
Received 66 Upvotes on 61 Posts
Ya, what nap and Ed said about electrical theory.

As far as a more efficient electric basebord all resistance heating is 100% efficient.
The only difference between different types of electric heat is how it is transfered to the occupied space.
The only thing you can do to improve it is change the way it is distributed.
In cold climates an electric ducted forced air system is usually preferred over baseboards.
 
  #10  
Old 02-18-07, 12:42 AM
nap's Avatar
nap
nap is offline
New Member
Join Date: May 2006
Location: north
Posts: 4,162
Upvotes: 0
Received 1 Upvote on 1 Post
Originally Posted by mchrist View Post
If I could, let me present an example:
A standard outlet with a lamp plugged into it. The lamp has a 60 watt bulb. Will the "circuit" (lamp) draw only 60 watts, and the neutral will have a voltage of zero? What is the current on the hot wire leading into the outlet?

I do appreciate your time and information. My wife tells me that I'm too curious for my own good. But I'm not curious enough to climb the pole and check out the POT, whatever that is.
let me try to quench your thirst for knowledge.

the only reason the neutral reads 0 volts is that is the leg that is grounded and I presume you are speaking of measuring "to ground". voltage is what is termed a "difference of potential between two points". So with that in mind, understand that the voltage read depends upon what 2 points you are utilizing.

In fact, if you were able to remove the neutral-ground connection, everything would still work BUT you would no longer read 0 volts to ground from the neutral wire. Due to capacitive coupling (won't take the time at the moment to explain this) you will generally read somewhere between 0 and 120 volts to ground on both the hot and neutral legs with the total of the 2 added together being around 120 volts. If you read from leg to leg, you will have your same old 120 volts, the same as before.


The neutral-ground connection gives you a 0 reference point to measure voltage to.


now to the current on the hot wire leading to a 60 watt lamp.

It will be the same as the current on the neutral leaving the 60 watt lamp which would be 1/2 amp

P(power(in watts) = E (voltage) X I (amps) or in different form I=P/E

the current is present in the neutral, just as it is in the hot leg.
 
  #11  
Old 02-18-07, 06:33 AM
M
Member
Thread Starter
Join Date: Jun 2001
Location: Pennsylvania
Posts: 247
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks to all for their input. This has been a great thread!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: