Re: Fire Wire Solid vs. Stranded

[ABLE1 <someone@xxxxxxxxxxx>]

On 10/30/2015 9:07 PM, doug wrote:
> "ABLE1" <someone@xxxxxxxxxxx> wrote in message
> news:JuSYx.2077$PV4.738@xxxxxxxxxxx
>> On 10/30/2015 5:45 PM, doug wrote:
>>>
>>> "ABLE1" <someone@xxxxxxxxxxx> wrote in message
>>> news:NyPYx.23345$bG2.5135@xxxxxxxxxxx
>>>> Bob,
>>>>
>>>> I can see that THHN would be acceptable in conduit.  Back in the day
>>>> most
>>>> older
>>>> schools had 120vac bells.  I pulled one a couple of years ago that
>>>> was that way.  There were just pull stations and they were a hot loop on
>>>> 120vac.
>>>> It was so old it had whiskers and a cane.
>>>>
>>>> It has always been my belief that you had to use solid since if using
>>>> stranded
>>>> you would have perfect supervision on just one strand if others were
>>>> broken.
>>>> But, then when it went into alarm that one strand could not handle the
>>>> load
>>>> and the system would fail.  With solid that would not happen.
>>>>
>>>> Les
>>>>
>>>
>>> This link explains when and why it was changed to allow stranded scroll
>>> down
>>> to Sec.760-71(a)
>>>
>>> http://ecmweb.com/content/illustrated-changes-1996-necode-part-4
>>>
>>>
>>> Doug
>>>
>>
>> Thanks Doug,
>>
>> Changed in 1996!!  Wow, that is very interesting.
>> Not that I will change my practice of installing solid, but I will now
>> not question anyone that does.  Well maybe I will a little bit.
>>
>> Again thanks for filling in the blanks.
>>
>> Give yourself a pay increase for excellent research abilities.
>>
>> Les
>
> Another common assumption seems to be that 3/4" is the minimum size for
> conduit runs for fire alarm systems, consequently you see many installations
> that have 3/4" conduit to device with only a 18/2 cable inside. A lot of
> electricians will swear blind that it is a national code requirement.
>
> Doug
>

There is an old school that I do a lot of work for including the Master
Clock system.
When the school was built in the early '80's or so, there is a single
3/4" conduit
that goes from the Master Clock in the office through out the building
(2 floors)
to every room or space that has a clock and it carries just one(1) #12
solid wire.
It is a hot for the clock correction at 120vac.  Every hour it is
energized for
6 seconds "@ 58 minutes" for 1 hour correction and at 6am and 6pm it is
energized
for 12 seconds for 12 hour correction.

Have heard that some teachers have complained that the 6 second buzz
from the clock
on the hour is a distraction to their students.  Really???

Les