Electrical Assistance

[saintsfanbrian]

My wife has taken up pottery. She doesn't enjoy going to the studio where she took lessons to fire her creations so we purchased a 120 volt kiln for her to work on at home. The device works great unless she is trying to fire her "green ware" which is the initial firing after creating something. The kiln needs to get to around 1900 degrees. The problem we are finding is that the voltage drops when the kiln heating elements are active. The voltage at the outlet is 120 with out any load. When the kiln "kicks in" the voltage drops to 113. This is on a dedicated 15 amp circuit with NO OTHER devices on it.

What can I do to keep 120 volts going to the kiln?

[dralarms]

My wife has taken up pottery. She doesn't enjoy going to the studio where she took lessons to fire her creations so we purchased a 120 volt kiln for her to work on at home. The device works great unless she is trying to fire her "green ware" which is the initial firing after creating something. The kiln needs to get to around 1900 degrees. The problem we are finding is that the voltage drops when the kiln heating elements are active. The voltage at the outlet is 120 with out any load. When the kiln "kicks in" the voltage drops to 113. This is on a dedicated 15 amp circuit with NO OTHER devices on it.

What can I do to keep 120 volts going to the kiln?

Removed usless information

Edited October 19, 2008 by dralarms

[saintsfanbrian]

So a 30 amp breaker will allow me to have a greater voltage?

[saintsfanbrian]

Oops I just checked it is a 20 Amp breaker which is recommended by the manufacturer

[Guest tnmale46]

what size wire is going to it and how far is it from the panel

[Guest m&pc9]

Do not put a larger breaker on a circuit unless your wire size is big enough

I would use a #12 wire up to 20 amps

and #10 for the 30 amp

[DaveTN]

So a 30 amp breaker will allow me to have a greater voltage?

No, and neither will larger wire.

The voltage at the outlet is 120 with out any load. When the kiln "kicks in" the voltage drops to 113. This is on a dedicated 15 amp circuit with NO OTHER devices on it.

What can I do to keep 120 volts going to the kiln?

Is there a problem? A voltage drop may be normal. Is the kiln not getting hot enough?

Edited October 18, 2008 by DaveTN

[dralarms]

Edited October 19, 2008 by dralarms

[Guest Watauga]

What are the power specs (watts) for the kiln? volts X amps = power

Be careful with changing out panel breakers.

You really need to know positively the size of wire from the breaker panel to the kiln outlet.

I have seen houses where the wire size at the panel is not the same as the outlet.

Also, the distance between the breaker and outlet is important. Long distance needs bigger wire.

Resistance heaters draw lot of amps.

[saintsfanbrian]

120 volts and 15 amps is what the thing is rated for. It is not getting hot enough quick enough. Basically it has a set amount of time it is supposed to run for and since it cannot get up to 1900+ degrees in the allotted time it fails to finish.

We contacted the manufacturer and since we are getting an 6% drop in voltage it is getting a 6% drop in max temp which is causing it not to get hot enough.

As for distance linear feet is about 20 from panel to outlet. Now if it is running through the attic (which I suspect) you are probably talking more like 100'.

As for power -

15 amps

120 volts

1800 watts.

Should I just get an electrician to come out and run a new 12 gauge 20 amp run to the garage which is where the kiln is?

[DaveTN]

I do have to say I'm sorry for the "short" answer to change the breaker to a 30 amp, my thinking is it's better to have a bigger breaker than drawing too much power from a smaller one. Say you have a appliance that "needs" (or is rated at 20 amps) 20 amps then a 15 amp breaker will cause damaged to the unit and your house as well but a 30 amp breaker will protect the wiring by not letting it over heat.

A breaker does not control the amount of current (amps). If your device needs 20 amps for more than a short time a 15 amp breaker will kick.

If you put a 30 amp breaker on 14 wire there is a good chance of catching the house on fire before wires melt and short together; kicking the breaker.

If I’m not mistaken; as amperage increases voltage decreases. That is what he is seeing.

The breaker is not kicking out so I am assuming that the unit is not pulling more than it should. That is why my question about “is it not getting hot enough?â€.

My casual observation is that the electrical is fine. If the unit is not reaching the temperature it is suppose to be at… the POS is broke, take it back and get a new one.

[Guest Watauga]

Do the kiln specs require a dedicated circuit?

When the kiln is operating do you notice any lights dimming, etc?

My calcs: 113v X 15a = 1695 watts. That is 105 watts less than max.

My initial thought is this is not your problem.

Most power companies never provide the exact voltage; 240/120 or 208/117. They have a tolerance range of several percent.

Most appliances are designed to operate within this tolerance.

Is it possible to move the kiln near your breaker panel and run a short cable to the breaker?

For 1800 watts, I would use 12 gauge and a 20 amp breaker.

I would NEVER run a 1800 watt appliance on a 15 amp circuit.

Edited October 19, 2008 by Watauga

[dralarms]

If the unit is not reaching the temperature it is suppose to be at… the POS is broke, take it back and get a new one.

Yoiu are probally right.

[Guest m&pc9]

Your wire size and lenth of the run will cause a voltage drop.

I would think about having a 20 amp circuit ran to the garage ( because the mfg spec.) and try that before I would throw the furnace out.

If it is a pos then you still need a 20amp circuit for your new purchase. But if it were me and had to buy another I would try to find a 220v furnace it will be better on your electic bill and most likly heat up faster

[Guest m&pc9]

Do you have acess to an amp meter? you could check the amps the furnace is drawing it could have a burned out element. Ive never delt with a ceramic furnace but I have in the past worked with muffle furnaces and most of them had 2-3 different circuits so when they would get up to temp. they would cycle 1 or 2 circuits so it wouldnt go all the way off, and it would hold temp more precise

And if its not pulling full amps it could be a bad thermostat,relay or element

[enfield]

If the kiln manufacturer recommends a 20 amp breaker, that's telling you that your kiln draws over 15 amps and you need a 20 amp circuit, at least, to run it. I'd have a new, separate circuit installed with 12 gauge wire and a 20 amp breaker.

The voltage drop you're seeing is from trying to draw more current from the circuit than it's capable of providing at 120 volts. You shouldn't see more than a 2% drop under load.

The wire size used in the circuit dictates how big the breaker should be. A 12 gauge circuit can safely have no larger than a 20 amp breaker installed. Circuit breakers keep your house from burning down. Don't EVER install a bigger breaker in place of a smaller one.

Edited October 19, 2008 by enfield

[Guest bkelm18]

If the kiln manufacturer recommends a 20 amp breaker, that's telling you that your kiln draws over 15 amps and you need a 20 amp circuit, at least, to run it. I'd have a new, separate circuit installed with 12 gauge wire and a 20 amp breaker.

The voltage drop you're seeing is from trying to draw more current from the circuit than it's capable of providing at 120 volts. You shouldn't see more than a 2% drop under load.

The wire size used in the circuit dictates how big the breaker should be. A 12 gauge circuit can safely have no larger than a 20 amp breaker installed. Circuit breakers keep your house from burning down. Don't EVER install a bigger breaker in place of a smaller one.

His breaker isn't kicking (or at least he hasn't said it is). So the machine isn't trying to draw that much more amperage. And 12ga wire can handle more than 20 amps safely, regardless of what the code/regulations say. So saying to NEVER install a bigger breaker is too much of a blanket statement. If you're running 10ga wire on a 15 amp breaker, then by all means upgrade the breaker. Running 20-30 amps on 12ga wire isn't going to burn your house down. Would I recommend it? No. But with as much stupid crap as I've had to design/build/repair on a ridiculously small budget at my job, I've seen much worse.

[DaveTN]

So saying to NEVER install a bigger breaker is too much of a blanket statement.

Never install a larger breaker.

(If you have to ask on an internet forum)

Running 20-30 amps on 12ga wire isn't going to burn your house down.

It very well could. The current density at 30 amps is too high for #12 wire. One bad connection on the circuit and something will probably be on fire. 30 Amps must be at least #10 wire.

Would I recommend it? No. But with as much stupid crap as I've had to design/build/repair on a ridiculously small budget at my job, I've seen much worse.

I don’t remember the number, but it’s like 200 houses a day burn down due to faulty wiring. You don’t get pick the size of wire based on price.

[saintsfanbrian]

Okay - so calling the electrician it is. At minimum he will put in a different breaker and at max he will put in a 220 run and we will get a different kiln.

[DaveTN]

Let us know what he finds.

Compare the cost of running a 220 line with the cost of adding a 50 amp sub panel.

[saintsfanbrian]

I am sure he will now, but how would that work. Run a 50 amp run to the garage and put in a few breakers there? That sounds like an AWESOME idea so I can actually run a couple of Power tools in there too. Maybe even a package unit for heat and air.

[Guest colrmccoll]

I may be too late with this response but here is what is happening. This is a circuit composed of two resistive elements., the kiln and the wiring. The total voltage will be dropped by each in proportion to the overall resistance of each; ie, 113volt (I think you measured) drop across the kiln leaves a 7 volt drop across the wiring (assuming 120 volts available). Now, if you know how much current is flowing in the circuit, then you know (calculate) how many watts are being consumed by the wiring. watts = volts x amps.

The breaker is there to protect the wiring. You can increase the wiring size and minimize the wiring resistance. This would produce more voltage across the kiln and hence more watts in the kiln.

You could also move the kiln closer to the breaker and shorten the wiring.

I could calculate this knowing the length of wiring but I would guess it is marginal.

It is not an easy answer to this but would be glad to answer any further questions.

Rick

[DaveTN]

I am sure he will now, but how would that work. Run a 50 amp run to the garage and put in a few breakers there? That sounds like an AWESOME idea so I can actually run a couple of Power tools in there too. Maybe even a package unit for heat and air.

Sure…. Then if you need power you just have to run an outlet from the sub.

You wife may decide she wants to Arc Weld while her pottery is being cooked. You may want to run a big compressor, Lathe, Milling Machine or Grinder. You might want to add a Phase Converter and run a three phase CNC milling machine; you just never know.

Available amps in a garage is like money…. You can never have too much.