Installation details [RE-wrenches]

[matthew tritt]

Electrical,

It appears as though I've been laboring under a misconception for a great
number of years about this. (I was admonished loudly once by an inspector
years ago for mixing ac and dc in the same conduit - it stuck)
But mixing them in the same switch box gives me the heebie-jeebies! That
seems like a recipe for bad juju
to me.

Matt
----- Original Message -----
From: "Electrical Energy" <solar at eagle-access.net>
To: <RE-wrenches at topica.com>
Sent: Wednesday, November 27, 2002 5:15 PM
Subject: Re: Installation details [RE-wrenches]


> Here is the Code quote.  Below it is the discussion from the explanatory
> section of the NEC Handbook.  The explanation really clears things up.  It
> seems Jay is doing it right.
>
> In a system not solar photovoltaic, conductors don't need separation, as
> long as the system is under 600 volts and the insulation of all conductors
> is adequate for the conductor of the highest voltage.
>
> I'd also think that battery powered DC circuits could be in the same
switch
> boxes as AC from the inverter.  Would the power system supplied by the
> solar voltaic system be subject to the rules of photovoltaic systems?
>
>
> CODE QUOTE
> (C) Conductors of Different Systems.
> (1) 600 Volts, Nominal, or Less. Conductors of circuits rated 600 volts,
> nominal, or less, ac circuits, and dc circuits shall be permitted to
occupy
> the same equipment wiring enclosure, cable, or raceway. All conductors
> shall have an insulation rating equal to at least the maximum circuit
> voltage applied to any conductor within the enclosure, cable, or raceway.
> Exception: For solar photovoltaic systems in accordance with 690.4(B).
> FPN:See 725.55(A) for Class 2 and Class 3 circuit conductors.
>
>
> Explanitory remarks from the NEC Handbook.
> Section 300.3(C)(1) makes it clear that it is the maximum circuit voltage
> in the raceway, not the maximum insulation voltage rating of the
conductors
> in the raceway, that determines the minimum voltage rating required for
the
> insulation of conductors for systems of 600 volts or less.
> The conductors of a 3-phase, 4-wire, 208Y/120-volt ac circuit; a 3-phase,
> 4-wire, 480Y/277-volt ac circuit; and a 3-wire, 120/240-volt dc circuit
may
> occupy the same equipment wiring enclosure, cable, or raceway if all of
the
> conductors are insulated for the maximum circuit voltage of any conductor.
> In this case, the maximum circuit voltage would be 480 volts, and 600-volt
> insulation would be suitable for all of the conductors.
> If a 2-wire, 120-volt circuit is included in the same raceway with a
> 3-wire, 120/240-volt circuit having 600-volt conductors, then the 2-wire,
> 120-volt circuit conductors could use 300-volt insulation because the
> maximum circuit voltage is only 240 volts.
>
> Section 690.4(B) prohibits the location of solar photovoltaic circuits
> within the same enclosure as conductors of other systems unless the
> conductors are separated by a partition or are connected together.
>
> Section 725.55(A) prohibits Class 2 and Class 3 circuit conductors from
> occupying the same enclosure, cable, or raceway as Class 1, electric
light,
> and power conductors, unless specifically permitted in 725.55(B) through
(J).
> (At 08:51 AM 11/27/2002 -0800, you wrote:
> >Hi Bob-O,
> >
> >I've run AC and DC in the same gutter, code approved.
> >
> >I interpret the " must be seperated by a partition or are connected
> >together" to
> >mean that if I wire tie the AC side to each other and the DC side to each
> >other
> >they are connected together.
> >
> >I for one will continue to use the gutter system unless there is clear
> >reason not
> >too.
> >
> >Thanks ,
> >
> >jay
> >
> >Peltz Power
> >
> >
> >
> >"Bob-O Schultze, Electron Connection" wrote:
> >
> > > Max,
> > > Really good point. I've put them both in the same gutter in a
> > > multiple inverter system before with no beef from the inspector, but
> > > the 690 part forbidding PV input and output circuits in the same
> > > chase can be interpreted to disallow that practice. Personally, I've
> > > always read it as not wanting DC output circuits in the same run as
> > > PV inputs which would be at a somewhat higher voltage. It's ANOTHER
> > > of those goofy 690 rules that are ill defined and unsupported by
> > > facts.
> > > BOb-O
> > >
> > > >Graham, I was looking at the layout for the 2500's. It appears that
> > they are
> > > >mixing the ac / dc wiring in the gutters. Do you know if they had
barriers
> > > >in the gutter, or do they occupy the same space?? I have had
> > discussion with
> > > >inspectors over the issue of a gutter below the inverter that takes
the
> > > >ac/dc feeds in and out of the inverter. The wires are in the same
> > space once
> > > >they enter the inverter enclousure so why not allow  a gutter below
the
> > > >inverter that makes a convienient and clean way to feed both ac and
dc
> > from
> > > >the conduit runs into the inverter?? This works well as in this
> > install with
> > > >multiple inverters.......
> > >
> > > - - - -
> > > To send a message: RE-wrenches at topica.com
> > >
> > > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
> > >
> > > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
> > >
> > > Check out participant bios: www.mrsharkey.com/wrenches/index.html
> > >
> > > Hosted by Home Power magazine
> > >
> > > Moderator: michael.welch at homepower.com
> > >
> >
> >- - - -
> >To send a message: RE-wrenches at topica.com
> >
> >Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
> >
> >List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
> >
> >Check out participant bios: www.mrsharkey.com/wrenches/index.html
> >
> >Hosted by Home Power magazine
> >
> >Moderator: michael.welch at homepower.com
> >
>
> - - - -
> To send a message: RE-wrenches at topica.com
>
> Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
>
> List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
>
> Check out participant bios: www.mrsharkey.com/wrenches/index.html
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>
>
>
>

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================