Re: mixed voltages in Altronix ALTV244 box

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On 3 Dec 2005 14:57:45 -0800, smile4camera@xxxxxxxxxxxxx wrote in message
<1133650665.547577.92230@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>
>Marc F Hult wrote:
>> On 3 Dec 2005 12:53:01 -0800, smile4camera@xxxxxxxxxxxxx wrote in message
>> <1133643181.543560.222080@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
>>
>> > I didn't spec the job or buy the parts, all I'm doing is putting it
>> >all together. The power supply seems to be commonly available here in
>> >NA.. does the lack of a UL listing mean it's not (supposed to be)
>> >allowed to be sold in the US?
>> >
>> > Jim
>>
>> Jim,
>>
>> Among other reasons, one can sell things that would violate building codes
if
>> installed for a particular use in part because whether they conform to codes
>> depends in part on their actual application.
>
> I can understand that <g>.. what I was questioning was his statement
>that the power supply I mentioned isn't available to North America
>because it's not UL approved. It _is_ available, and I was asking for
>clarification because it seems that he was saying UL listed is required
>for sale in NA?..
>
>
>>
>> As designed, the power supply would appear to meet the basic requirements of
a
>> source for Class 1 low-voltage circuits as per NEC Articles 720 and 725
which
>> specify =< 30 volts and =< 1000VA. I don't recall what the isolation
>> requirements are.
>>
>> Since it is not _marked_ as Class 2, whether it electrically meets the
>> requirements of Class 2 is moot. But a listed Class 2 can be treated as
Class 1
>> even if it has lost its marking. But that in turn means that the wiring from
it
>> has to conform to NEC Chapter 3 requirements which are the same as for
'normal'
>> 110 & 220 AC except, if I recall correctly, conductors as small as 18 AWG
may
>> be used but no smaller. Most Chapter 3 conductors have to be at least 14AWG.
>>
>> But whether it will satisfy an inspector once installed is a different
matter.
>> If you know where it is to be installed, get a pre-installation opinion from
>> the/an inspector ("Authority Having Jurisdiction" -- AHJ for short -- in the
>> parlance of the NEC).
>>
>> Don't take my word for it, ask your inspector ... Marc
>> Marc_F_Hult
>> www.ECOntrol.org
>
> On this job, I'm lowest man on the totem pole. This is an assumption,
>but as the engineer who designed the install and the lead tech doing
>this are both keeping their fingers in the job I'm sure I'll be advised
>long before an inspector makes their way here. I've only just started
>in this arena of work.. but it does look interesting, and I hope to go
>far with it.
>
> Thanks for the response..
>
> Jim

You are welcome. Sometimes the less one knows technically, the better one is
able to cope with regulatory requirements  -- a hopefully gentle way of
implying that if the engineers and other techs you work with are not familiar
with the NEC, they may find it counterintuitive. ("The circuit only needs 50 mA
of 12vdc but the inspector says we have to replace all the wire we ran with at
least 18 gauge conductors inside conduit ?!% ").

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org