Thumbs down on Paragon kilns

As I’ve discussed previously, Paragon kilns do not follow the National Electrical Code (NEC) on the plugs that are used on their kilns. For example, their Bluebird kiln draws 14 amps, Paragon states the kiln requires a 20 amp dedicated circuit, but, believe it or not, they use a standard 15 amp plug.

Here’s an e-mail conversation I had with Arnold Howard of Paragon:

I am writing to you today to bring to your attention an issue that concerns me as a person who is deeply interested in safety in the glassworking studio. Recently, on several of the glassworking forums, issues have come up relating to people continually blowing circuit breakers and fuses when running their kilns. Naturally, I began to do some research and found that a large number of kilns that are available in the US, provided by your company and others, do not meet the requirements of the US National Electrical Code, sections 210.21 and 210.23. Continue reading

More on in-line fans

I’ve been asked my opinion on the Vortex and CAN FAN in-line fans; so I did some basic research.

I can’t recommend the Vortex line simply because the manufacturer does not provide the static pressure curves for their fan lines. This is very important because you need to know how a given fan will perform in your exhaust system. A given fan might have a CFM output of 650 CFM at zero inches of static pressure (free air), but what is its output at a half inch or more of static pressure? It could very well be far less, and in that case, the fan is not meeting your design criteria. Continue reading

Unbelievable, simply unbelievable

It must be very expensive to consult with an electrician, or hire a licensed electrician to have on your staff. I’ve just spent several hours going through the websites of the major kiln manufacturers: Paragon, Skutt, Jen Ken and AIM. Everyone one of these kiln manufacturers is in violation of the US NEC (National Electrical Code) on at least one of their kilns.

Let’s take Paragon as an example. Of their line of approximately 46 electric kilns, only 10 had the proper plug on the kiln power cord as well as the proper recommended circuit breaker for the kiln. Several of their kilns draw 20 amps, and Paragon uses a 20 amp plug and recommends a 20 amp circuit breaker!

No wonder people have problems using their kilns.

I can’t help but wonder if anyone at any of these kiln manufacturers even has a copy of the current NEC code, much less consults it on a regular basis.

I can certainly understand the design philosophy (although I totally disagree with it!) that they (the kiln builder) wants to have a kiln that will plug into an ordinary outlet (rated at 15 amps). But what I don’t understand is why they can’t simply build the kiln so that it draws a maximum of 12 amps.

There is no excuse for putting their customers at risk by providing equipment that does not meet the National Electrical Code.

More on amperage ratings for kilns

I’ve received some feedback from folks wanting more information about my previous post “The rule of 80% and kilns“.

First, here is a direct link to the NEC (National Electrical Code): (scroll to near the bottom of the page and click on the link that says “View the 2008 edition of this document”)

The important sections are 210.21 and 210.23. In part, they say:

Table 210.21(B)(2) Maximum Cord-and-Plug-Connected Load to Receptacle

Circuit Rating …………………… Receptacle Rating ………………. Max Load (Amperage)
15 or 20 Amps ………………………. 15 Amps ……………………………… 12 Amps
20 Amps ………………………………. 20 Amps ……………………………… 16 Amps

210.23 Permissible Loads

(1) Cord-and-Plug-Connected Equipment Not Fastened in Place

The rating of any one cord-and-plug-connected utilization equipment not fastened in place shall not exceed 80 percent of the branch-circuit amperage rating.

Continue reading

The rule of 80% and kilns

For some time now, I’ve been watching a running debate about how much power a kiln uses on a given circuit. Over on WC there is a thread about the circuit breaker always kicking out, and it turns out that the person has a kiln that draws 14 amps and is running it on a 15 amp circuit (along with other appliances and devices).

Under the National (USA only) Electrical Code (NEC), a device that draws 14 amps needs to be on a 20 amp circuit. The reason for this is what is referred to as the Rule of 80%. In brief, a given circuit should have a load of no more than 80% of its marked value: for a 15 amp circuit, that’s 12 amps, for a 20 amp circuit, that’s 16 amps. Continue reading

E-mail questions, part one

Hi,I see that you are recommending normal fans instead of heat-proof ones — does this also work for big torches (I’m getting a 50mm Zenit burner in 2 weeks)?

If I buy a normal fan, what do I need to look out for — because if the air is cool enough for a normal fan to handle, are plastic blades ok?

Do I need to make the vent to the fan longer to compensate for the temps, and if so, how long?

I’d love to see a public post about this, I’m sure other people are also wondering about this, and the price difference between a heatproof fan and a normal one is huge in Europe, the fan can easily cost me more than the torch did!


thanks for the blog,

Heat is not “typically” an issue, however, with larger torches and “larger/longer” flames, heat can become an issue. The reason heat isn’t usually an issue is because of dilution — we are moving a lot of air through the system per minute, upwards of 800 CFM. Any heat that is generated inside the work area is going to get diluted by that large air flow. However, a large enough torch is going to generate enough heat to overcome that dilution, and that is something you have to watch for. Continue reading

It is called Responsibility, Dale

From LE:

And Yes I’m the guy that does not see quite the danger the others see if you use a good quality commercially manufactured hose from a reputable supplier…

When someone decides to start giving safety information, they take a burden upon themselves to provide correct and proper information, as well as being sure that the information you provide does not put someone at risk.

When there is a preponderance of information provided by other knowledgeable people and you are the lone wolf, perhaps it is time to reconsider the basis of your stand.

We have a responsibility to our fellow glassworkers when we provide safety information. That responsibility includes following all of the National Codes, the law and the rules as set forth by the various regulative bodies. Case in point is the use of the so-called high pressure hose assemblies for using a bulk tank with a hot head torch. Continue reading