Jump to content

Running a 208v single phase kiln at 240v


Recommended Posts

From what I’ve found (which is not too much) this should work fine if the elements are replaced with 240v elements, and maybe replacing the relays would help? Am I missing anything? I can buy a 208v kiln at a good price so I’d like to know. It’s a Paragon TnF-23-3

240v single phase, 47 amps. 

thanks!

Link to comment
Share on other sites

2 hours ago, AaronRotchadl said:

From what I’ve found (which is not too much) this should work fine if the elements are replaced with 240v elements, and maybe replacing the relays would help? Am I missing anything? I can buy a 208v kiln at a good price so I’d like to know. It’s a Paragon TnF-23-3

240v single phase, 47 amps. 

thanks!

Usually it's just a matter of changing out the elements, but contact Paragon to make sure for that specific model.

Link to comment
Share on other sites

  • 2 weeks later...
  • 2 weeks later...
11 hours ago, ronfire said:

I think you can run the elements until they burn out. They will not last as long as 240v elements.

 

Because of the difference in the resistance of the elements, if you run 208 volt elements on 240 volts you'll be pulling more amperage, which can be a problem. For instance, a kiln pulling 48 amps on 208 volt service will pull about 55 amps on 240 volt service. That means the 60 amp breaker is no longer within code.

Link to comment
Share on other sites

On 7/2/2020 at 7:32 AM, neilestrick said:

Because of the difference in the resistance of the elements, if you run 208 volt elements on 240 volts you'll be pulling more amperage, which can be a problem. For instance, a kiln pulling 48 amps on 208 volt service will pull about 55 amps on 240 volt service. That means the 60 amp breaker is no longer within code.

Good to know, never thought about the amperage difference.

Link to comment
Share on other sites

  • 6 months later...

I realize this is an older thread but I've got this same issue.  I got a 208v single phase kiln for FREE but trying to figure out how to run at home.  If my only concern is burning out the elements quicker that's ok with me since it was free but is there any safety concerns?  I saw the post here about the amps overloading the breaker.  Mine is 24amps at 208 how do I calculate what that will be on 240?

Link to comment
Share on other sites

@vcasey 

Ohm's Law:

Watts = Volts x Amps
Amps = Volts / Ohms
Ohms = Volts / Amps

So if we take 208 volts divided by 24 amps we get 8.66 ohms. Then take 240 volts divided by 8.66 ohms we get 27.7 amps. Electrical code requires that the kiln be on a breaker that is 25% greater than the draw of the kiln but not more than 50% greater. So at 24 amps you need a 30 amp breaker. On 240 volts at 27.7 amps you'll need a 40 amp breaker. The 40 amp breaker will need larger wires, so it will cost you more to hook it up. When you change to 240 volt elements it will likely still be a 24 amp kiln, however the 40 amp breaker will still be within code.

If I were you, since you're starting fresh, I'd pull large enough wires to run a 60 amp service out there (at least 6 gauge) in case you ever decide to move up to a larger kiln. Put in a sub-panel or fused disconnect near the kiln with whatever size breaker you need for the current kiln, and drop the outlet from that panel. It'll be an easy upgrade later if you get a bigger kiln that pulls more amperage.

 

Link to comment
Share on other sites

  • 11 months later...
On 1/5/2021 at 10:33 AM, vcasey said:

I realize this is an older thread but I've got this same issue.  I got a 208v single phase kiln for FREE but trying to figure out how to run at home.  If my only concern is burning out the elements quicker that's ok with me since it was free but is there any safety concerns?  I saw the post here about the amps overloading the breaker.  Mine is 24amps at 208 how do I calculate what that will be on 240?

How did running the kiln without replacing the elements work out for you??

Link to comment
Share on other sites

If we calculate the resistance of the elements at 208 v then  ohms= V/A we get 208/24 = 8.667 ohms. We know this to be true because that is how it was designed for 208 v and that is how it is operating. It pulls 24 amps at 208v.

Assuming no math errors (double check me)
If we run those elements now at 240 v we get: amps =volts/ohms or 240/ 8.667 = 27.69 amps.

Breaker size in the states needs to be 25% over rating but not exceed 50% for a continuous load (which a kiln is defined as) so 27.69 x 1.25 = 34.61 amps minimum and 27.69 x 1.5  =  41.53 amps maximum.

Nearest common breaker ought to be 35amp 2 pole wired with #8 copper wire or greater for longer distance runs.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.