Kiln installation

[K8MHZ]

I thought I had seem some with motors/blowers for the venting.

I used to build and install them. Of course, it was a while ago, but none I have seen had blowers. No vents, either.

 

[Finn12067]

I saw on their website that kilns over 48A should be hardwired. Although yours seems to be exactly 48A, according to you, it might be good if you have your electrician install a 60A fused disconnect and direct wire the kiln. Of course you would have to get permission from the mfg to prevent voiding your warranty.

 

[Finn12067]

Again thank you all for your interest and expertise - it’s been super helpful and you’ve helped me to noodle through my next steps .
I will post back when I hear back from MEC (the national certifying agency.)
after a conference call w the electrician, the electrical inspector and town building head this am - they are standing on the 50 amp breaker . The electrician has offered to hardware the kiln at no additional charge - if I can get ok from l&l to honor the warranty in that case.
So that’s where it stands - hopefully l&l will play along .
it would appear that the customer is caught between many sets of code/ regulations - this is a grey area and from other posts even on this forum - the plug is becoming an issue for many customers and electricians . Based on a very superficial understanding of the issue I get why electricians would have an issue w putting it on a 60 amp breaker.
Wish me luck lol

 

[hillbilly1]

i had a customer request a buck/boost transformer be installed to drop the voltage down to 208. They said the heating elements were expensive to replace, so the lower voltage extended the life of the elements. I wired one for my baby sister about seven years ago. At first she wanted a meter down at the building she put it in, but I convinced her to just run a feed off my meter down there (about 100’) since she was only going to use it twice a year. It still has never been used! LOL!

 

[Finn12067]

i had a customer request a buck/boost transformer be installed to drop the voltage down to 208. They said the heating elements were expensive to replace, so the lower voltage extended the life of the elements. I wired one for my baby sister about seven years ago. At first she wanted a meter down at the building she put it in, but I convinced her to just run a feed off my meter down there (about 100’) since she was only going to use it twice a year. It still has never been used! LOL!

Too funny !

 

[Meltric_South]

the plug is becoming an issue for many customers and electricians . Based on a very superficial understanding of the issue I get why electricians would have an issue w putting it on a 60 amp breaker.

As was mentioned before you may have concerns from the manufacturer of voiding the warranty from modifying the equipment, and I know several people watching the board already know this, but I thought I would mention 60A plugs and receptacles exist.

 

[kwired]

Kilns don't have blowers.

-Hal

If they do it would likely be a pretty small blower, and any 125% factor would be on the motor only not the heater elements.

 

[kwired]

Did this unit come factor wired with the 50 amp cord/plug or did someone else put it on? Distributor maybe?

Instructions should indicate what the supply options are, particularly if there is more than just one option.

I have to agree with others in that this unit is not very likely to draw full rating for more than 3 hours. It will cycle on/off as needed to maintain temperature setting.

 

[Finn12067]

As was mentioned before you may have concerns from the manufacturer of voiding the warranty from modifying the equipment, and I know several people watching the board already know this, but I thought I would mention 60A plugs and receptacles exist.

Thank you for pointing that out again - gives me another option if the manufacturer won’t stand by
The warranty

 

[winnie]

For what its worth, we discussed this about 6 years ago, with no good conclusion:

CAN KILN BE CORD & PLUG CONNECTED?

I have an electric pottery kiln rated 240v, 11,520va, which comes out to be 48 amps. This kiln can run easily 7 or 8 hours at a time. I realize my branch circuit conductors and OCPD have to be sized 125% of the load. My question is, does a device only have to be rated for the rating of the load...

forums.mikeholt.com

Looking forward to the justification for 50A receptacles on 60A circuits with 48A loads. It might be as simple as 'this is the way we've always done it' from a time when the practice was acceptable.

-Jon

 

[Finn12067]

For what its worth, we discussed this about 6 years ago, with no good conclusion:

CAN KILN BE CORD & PLUG CONNECTED?

I have an electric pottery kiln rated 240v, 11,520va, which comes out to be 48 amps. This kiln can run easily 7 or 8 hours at a time. I realize my branch circuit conductors and OCPD have to be sized 125% of the load. My question is, does a device only have to be rated for the rating of the load...

forums.mikeholt.com

Looking forward to the justification for 50A receptacles on 60A circuits with 48A loads. It might be as simple as 'this is the way we've always done it' from a time when the practice was acceptable.

-Jon

I will let you know what I find out but I think you are right - I had a like previous kiln installed approx 10 yrs ago and when the breaker and receptacle were installed - no questions / issues came up

 

[kwired]

For what its worth, we discussed this about 6 years ago, with no good conclusion:

CAN KILN BE CORD & PLUG CONNECTED?

I have an electric pottery kiln rated 240v, 11,520va, which comes out to be 48 amps. This kiln can run easily 7 or 8 hours at a time. I realize my branch circuit conductors and OCPD have to be sized 125% of the load. My question is, does a device only have to be rated for the rating of the load...

forums.mikeholt.com

Looking forward to the justification for 50A receptacles on 60A circuits with 48A loads. It might be as simple as 'this is the way we've always done it' from a time when the practice was acceptable.

-Jon

48 amp load that is non continuous can be on a 50 amp circuit, so it comes down to is this a continuous load or not. If it takes more then 3 hours to reach setpoint, then it should be considered a continuous load

 

[winnie]

48 amp load that is non continuous can be on a 50 amp circuit, so it comes down to is this a continuous load or not. If it takes more then 3 hours to reach setpoint, then it should be considered a continuous load

As I understand it: a 48A load that is non-continuous can be on a 50A circuit (50A breaker and wiring)
A continuous 48A load needs to be on a 60A circuit (60A breaker and wiring)

What the manufacturers instructions state for 48A kilns is a 60A circuit with 60A wiring and a 50A receptacle and plug, which seems a hybrid of the two allowed installations.

-Jon

 

[K8MHZ]

48 amp load that is non continuous can be on a 50 amp circuit, so it comes down to is this a continuous load or not. If it takes more then 3 hours to reach setpoint, then it should be considered a continuous load

From what I have read and the fact that this is common, I would hazard to guess the load is not continuous.

I used to repair kilns of this size and never went to solve a problem that looked like an overload. Mostly elements and bricks.

 

[electrofelon]

From what I have read and the fact that this is common, I would hazard to guess the load is not continuous.

I used to repair kilns of this size and never went to solve a problem that looked like an overload. Mostly elements and bricks.

I'm also in the definitely not a continuous load camp. This is one of these cases where the manufacturer says something stupid - they should let the electrician worry about the circuit sizing and just focus on making kilns