David Billington wrote:

DougC wrote:
On 7/26/2011 3:10 PM, David Billington wrote:

Which elements did you buy. The ones I'm used to have an outer metal
sheath which is insulated from the internal heating element
and it's advisable to ground the outer sheath in case of a short, rare
but it does happen. For item such as glass annealing ovens this also
saves having to have an isolation switch to turn off the power to the
elements when the door is opened which would be required for safety with
bare wire elements.

I got two of these-
part# 3540K36
36" long x .260" dia - 120VAC 750W - 36.45 each

I just poked around on them with a voltmeter and the outside is
isolated. Testing against one end and the sheath = open circuit, while
across both the ends is 19.7 ohms.

I saw the ceramic end caps and just assumed it had to be mounted only
by them.
I have real trouble loading any details linked on that site as it wants
me to give a user name etc, I did get details recently but can't
currently other than the item being a "tubular bendable immersion
heater" so it sounds the same as what I use in which case the outer
sheath is insulated from the inner heater with MgO IIRC. When I go to
http://www.mcmaster.com and enter a part number it just sits and spins
and is really annoying, it can be tricked into giving the details
sometimes. Maybe it's because I'm in the UK. If they were UK based I
would not do business with a website like that but I suspect that is not
the problem.


No problem here. I used Google Chrome for the browser.


--
It's easy to think outside the box, when you have a cutting torch.