Electrical Engineering - Maximum Draw on a Household Circuit?

Author

Maximum Draw on a Household Circuit?

Marc Miller

2005-07-24, 9:03 pm

I'm no electrician so I thought I post a question. What's the maximum draw
that can be connected to a standard household circuit? I have a 200amp
panel and just installed a circuit with numerous outlets and a fluorescent
light fixture on a 15amp breaker with 12/2 Romex. I put two duplex outlets
together so I would have four connections in the basement, and then the wire
was run to the garage to power the light as well as one duplex outlet. Just
curious as I don't want to get in trouble. Thanks...

keith

2005-07-24, 9:03 pm

On Sat, 23 Jul 2005 23:06:22 -0400, Marc Miller wrote:

> I'm no electrician so I thought I post a question. What's the maximum draw
> that can be connected to a standard household circuit?

Define "standard". In the US, few 120V outlets are rated for more than
15A, though many circuits are rated for 20A. Circuits are rated by
(and protected for) their wire size.

> I have a 200amp
> panel and just installed a circuit with numerous outlets and a
> fluorescent light fixture on a 15amp breaker with 12/2 Romex.

Why 15A?

> I put two duplex outlets together so I would have four connections in the
> basement, and then the wire was run to the garage to power the light as
> well as one duplex outlet. Just curious as I don't want to get in
> trouble. Thanks...

What's the total draw? If it's less than 15A, you should be fine. THough
I'd have run a seperate feed to the garage.

--
Keith

Pete J. Ahacich

2005-07-24, 9:03 pm

First of all, you could use a 20a breaker with 12/2.

120VAC 20 amp circuit per 500ft/^2 (Ref Table 220-3-b 1996 NEC) (Sorry. I
don't have a current code book handy to give you a ref # from.)

120Vx .80 = 16 amps; 16a/1.5a per light/outlet allows you 10 devices max.

"Marc Miller" <swimman@cox.net> wrote in message
news:kCDEe.67450$R21.37752@lakeread06...
> I'm no electrician so I thought I post a question. What's the maximum
> draw
> that can be connected to a standard household circuit? I have a 200amp
> panel and just installed a circuit with numerous outlets and a fluorescent
> light fixture on a 15amp breaker with 12/2 Romex. I put two duplex
> outlets
> together so I would have four connections in the basement, and then the
> wire
> was run to the garage to power the light as well as one duplex outlet.
> Just
> curious as I don't want to get in trouble. Thanks...
>
>

PCK

2005-07-24, 9:03 pm

"Pete J. Ahacich" <pjahacich@bellsouth.net> wrote in message
news:lhEEe.24346$do5.3614@bignews5.bellsouth.net...
> First of all, you could use a 20a breaker with 12/2.
>
> 120VAC 20 amp circuit per 500ft/^2 (Ref Table 220-3-b 1996 NEC) (Sorry.
> I don't have a current code book handy to give you a ref # from.)
>
> 120Vx .80 = 16 amps; 16a/1.5a per light/outlet allows you 10 devices max.
>
>
> "Marc Miller" <swimman@cox.net> wrote in message

really here any 20 amp circuit would require t-slot receptacles
and they allow 12 devices (100 watt per device loaded to 80 %)
on a 15 amp circuit. unless the load is fixed and then no limit to number
of devices so long as 80%. don`t ask about electric heat as now they
allow 100% circuit loading on fixed electric heat.

HorneTD

2005-07-24, 9:04 pm

> "Marc Miller" <swimman@cox.net> wrote in message
> news:kCDEe.67450$R21.37752@lakeread06...
>
> Pete J. Ahacich wrote:
> First of all, you could use a 20a breaker with 12/2.
>
> 120VAC 20 amp circuit per 500ft/^2 (Ref Table 220-3-b 1996 NEC)
> (Sorry. I don't have a current code book handy to give you a ref #
> from.)
> 120Vx .80 = 16 amps; 16a/1.5a per light/outlet allows you 10 devices
> max.
>

There is no maximum number of receptacle or lighting outlets prescribed
by code in the US NEC for residential occupancies. The 180 volt ampere
rule applies only to non residential occupancies.
--
Tom Horne

Well we aren't no thin blue heroes and yet we aren't no blackguards to.
We're just working men and woman most remarkable like you.

phil-news-nospam@ipal.net

2005-07-25, 10:21 am

On Sun, 24 Jul 2005 08:20:42 -0400 PCK <someone@somewhere.com> wrote:

| "Pete J. Ahacich" <pjahacich@bellsouth.net> wrote in message
| news:lhEEe.24346$do5.3614@bignews5.bellsouth.net...
|> First of all, you could use a 20a breaker with 12/2.
|>
|> 120VAC 20 amp circuit per 500ft/^2 (Ref Table 220-3-b 1996 NEC) (Sorry.
|> I don't have a current code book handy to give you a ref # from.)
|>
|> 120Vx .80 = 16 amps; 16a/1.5a per light/outlet allows you 10 devices max.
|>
|>
|> "Marc Miller" <swimman@cox.net> wrote in message
|
| really here any 20 amp circuit would require t-slot receptacles
| and they allow 12 devices (100 watt per device loaded to 80 %)
| on a 15 amp circuit. unless the load is fixed and then no limit to number
| of devices so long as 80%. don`t ask about electric heat as now they
| allow 100% circuit loading on fixed electric heat.

100% circuit loading is allowed for certain cases. Generally when the
circuit supplies a single load only, and that load is normally expected to
operate intermittently (such as a home electric central heat), running at
100% is safe. The 80% is otherwise a reasonable margin for the unexpected
such as variations in manufacturing tolerance and diversity in unplanned
loading.

In reality, you could run 30 amps on AWG 14 wire, and 40 amps on AWG 12
wire, or more, and not burn it up ... in most cases. The electrical code
standards build in a good margin of safety to cover lots of variations
that could all add up to turn a marginally safe situation into a very
unsafe one.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

2005-07-25, 5:21 pm

In article <dc2n0m11feu@news4.newsguy.com>, phil-news-nospam@ipal.net
wrote:

> On Sun, 24 Jul 2005 08:20:42 -0400 PCK <someone@somewhere.com> wrote:
>
> | "Pete J. Ahacich" <pjahacich@bellsouth.net> wrote in message
> | news:lhEEe.24346$do5.3614@bignews5.bellsouth.net...
> |> First of all, you could use a 20a breaker with 12/2.
> |>
> |> 120VAC 20 amp circuit per 500ft/^2 (Ref Table 220-3-b 1996 NEC) (Sorry.
> |> I don't have a current code book handy to give you a ref # from.)
> |>
> |> 120Vx .80 = 16 amps; 16a/1.5a per light/outlet allows you 10 devices max.
> |>
> |>
> |> "Marc Miller" <swimman@cox.net> wrote in message
> |
> | really here any 20 amp circuit would require t-slot receptacles
> | and they allow 12 devices (100 watt per device loaded to 80 %)
> | on a 15 amp circuit. unless the load is fixed and then no limit to number
> | of devices so long as 80%. don`t ask about electric heat as now they
> | allow 100% circuit loading on fixed electric heat.
>
> 100% circuit loading is allowed for certain cases. Generally when the
> circuit supplies a single load only, and that load is normally expected to
> operate intermittently (such as a home electric central heat), running at
> 100% is safe. The 80% is otherwise a reasonable margin for the unexpected
> such as variations in manufacturing tolerance and diversity in unplanned
> loading.
>
> In reality, you could run 30 amps on AWG 14 wire, and 40 amps on AWG 12
> wire, or more, and not burn it up ... in most cases. The electrical code
> standards build in a good margin of safety to cover lots of variations
> that could all add up to turn a marginally safe situation into a very
> unsafe one.

Wall socket outlets are rated at 7.5 amps each for a total of 15 amps
per wall outlet. At least that is what the imprint on some of mine says.

Al

Bud

2005-07-25, 6:21 pm

Al wrote:
>
>
> Wall socket outlets are rated at 7.5 amps each for a total of 15 amps
> per wall outlet. At least that is what the imprint on some of mine says.
>

Far as I know the UL standard for a 15A duplex receptacle is 15A per
half and 20A total (if they are on a 20A circcuit). They are tested at
150% of rating.

Bud--

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