Re: Far Side Chat -- Fire Alarm Code Issue

["Robert L. Bass" <robertlbass@xxxxxxxxxxx>]

>> Do you wait until the 110 VAC cables are removed from the breaker panel
>> before inserting the low voltage cables into the boxes?
>
> No Robert.  And I know where you're "steering"
> the discussion too.

In the US they won't allow us to run low voltage cables in the same box
unless there's a barrier or the cables are insulated to 600V.  I was
wondering if the requirements are the same there as here.

> your next "argument" won't work...

No argumnt... just discussion.

> There are many instances where low voltage and 110VAC cables are in the
> same electrical box (most FACP's are good examples)...

No disagreement on that, Frank.  However, if the AHJ sees low voltage wiring
in the octo-box for 110VAC smokes here, there will be an ...er, discussion.

> There's no way for you to connect a 24VDC
> door strike or strobe light (or your residential
> security panel) to a smoke alarm with a
> built-in relay (or compatible relay module)
> for instance, without "mixing voltages in the
> same box"...

It's not the voltage so much as the cables.  In the example you cited, a
door release relay has to be wired to the detector circuit and I'd be
surprised if an inspector gave you trouble for it.  FWIW, there are some
relays which are designed to fit in a J-Box knockout with the high voltage
on one side and the low on the other.  I don't know if any of them are
listed for this purpose though.  It might be interesting to find out.

> There is no US Code prohibiting such a connection (or situation)...

No need to anticipate an argument, Frank.  :^)

> The only proviso is that the high voltage and low voltage cables have to
> have a "physical
> separation" and/or be clearly marked as such
> to prevent confusion...

I think it's "and" rather than "or" but who's quibbling?

> Usually the "separation" is just a small piece
> of "Bakelite", but I've seen examples where
> there is nothing and the wires are just individually
> tagged.

I've also seen them separated with a stiff, hardboard-like material.  I
don't know what it's made of but some manufacturers use the stuff.

--

Regards,
Robert L Bass

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