"Bill" wrote in message
m...
I have a few questions he

I'm having installed a new furnace and tankless water heater in the
crawl space. Both use natural gas. There's about 4' or more of
height in the crawlspace.

Am I correct the each unit will require its own circuit? (The
tankless waterheater requires hardly any current, so kind of a waste
for an entire circuit.) I wonder if the tankless can come off an
exiting circuit -- locate an outlet next to the unit and use a cord
with a plug for the disconnect.

I also have been told that there needs to be lighting available for
both units. I assume that needs to be on a separate circuit, too.
Makes sense since the light would not be much help when servicing the
furnace with its power disconnected.

As for the lighting, is there anything better than a simple bulb
socket. In the crawl space I often worry about breaking the bulbs.

Next question, do junction boxes need to be secured? I hope I can
describe this:

My service panel is outside on an exterior wall. Currently, there's a
3/4" (EMT?) pipe that comes out (down from the panel) and through the
exterior wall (via an LB) and on the inside of crawl space the 3/4"
makes a 90 degree horizontal turn to make its run out to a subpanel.
I think there's 4 #8 wires in there.

I'd like to use that 3/4" to run another circuit from the panel into
the crawl space. The most convenient place would be where the 3/4"
makes the 90 degree bend. The problem is that's about 6" to 8" away
from the wall. So I could put a junction box there, but there would
be nothing to attache the box to except the 3/4" attached to the box.

That make any sense? So, the question is could the box be supported
by only the 3/4" that's coming in and out of the box?

Finally, that 3/4" EMT makes about a 4' or 5' run unsupported. It
feels very secure, but does that need to be supported better for code?

Thanks,


The furnace should have it's own circuit with a disconnect switch at the
unit. The disconnect may also require a fuse.....if the furnace nameplate
calls for one........usually a handybox switch/fuse combo is installed if
so.

Not a good idea to mess around with the 3/4" feeder conduit to the
subpanel.........could lead to some headaches. Probably easier to install
another 3/4" conduit in the same way that the subpanel feeder conduit is
ran....except keep going to the furnace, etc. A circuit can then be pulled
for the furnace and one circuit for the tankless water heater (and lights).
You need to look at the nameplate on the furnace to see it's electrical
requirements (usually a 15 amp circuit). If you install a receptacle for
the tankless water heater, like you said, that's the disconnect for it and
the lights can be on that circuit too. A switch for the lights needs to be
installed at the (most likely to be used) entry point to the crawl space.
You can install a light at each piece of equipment and control them with the
single switch. You can tap off of an existing circuit for the tankless
water heater and the lights, but if installing a circuit for the furnace,
probably easier to just pull that circuit in the conduit along with the
furnace circuit.

If you are concerned about the light fixtures, breaking bulbs, etc, Lowe's
sells a pretty beefy fixture with a thick glass globe protected by a metal
guard......(No. VT100G, SKU is 043114), kinda salty
though..........otherwise a keyless will do.