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#134803 - 11/30/02 02:15 AM Downlights  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,217
SI,New Zealand
What are the requirements, in your country,
for the installation of Flush-mounting Downlight fittings?.
We have a whole Code of Practice, for these types of lights, especially ELV Dichroics.
Your input please-


Let's face it, these days if you're not young, you're old - Red Green grin

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#134804 - 11/30/02 12:09 PM Re: Downlights  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Pretty much what you would expect: The final connection to the light made with heat-resistant flex (unless the terminal block is otherwise designated as taking NM directly), insulation cleared around and above the lamp to prevent overheating, fitted to a non-combustible surface (i.e. not the straw & plaster ceiling that somebody wanted me to install some in!).


#134805 - 12/15/02 01:08 AM Re: Downlights  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,217
SI,New Zealand
Man, if they only done it your way Paul,
Over here, the TPS, is fed straight into the
downlight fitting, no HR flex, no J-Box, no
nothing.
If I was wiring my own house, it would be done like you said.
Just a simple thing like clipping cables,
happen's very seldom over here.
It's just a big mess.


Let's face it, these days if you're not young, you're old - Red Green grin

#134806 - 12/15/02 08:05 AM Re: Downlights  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
The connection method I described is the way it should be done (and, of course, the way that I do it! [Linked Image]).

Sadly, I see so many of these things incorrectly installed exactly as you say: NM-type cable straight into the fitting. I frequently see the things completely enclosed in fiberglass insulation as well. I don't doubt that John & David will tell you the same thing.

Here's a typical example (copied from another thread);
[Linked Image]
Oh, and this one was supposedly fitted by a "professional!" [Linked Image]

By the way, I assume that your TPS is normal PVC-sheathed NM-type cable. Is TPS Tough Plastic Sheath? (We used to have an old TRS cable - Tough Rubber Sheath.)


[This message has been edited by pauluk (edited 12-15-2002).]


#134807 - 12/16/02 01:46 AM Re: Downlights  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,217
SI,New Zealand
Yes Paul,
TPS, is short for Tough-Plastic-Sheathed
cable.
What is NM cable?.
I note that in your penultimate reply, you
mentioned a straw and plaster roof, is that the cieling lining?.
How do they cope in areas of Devonshire and
such, that have thatched roofs?. [Linked Image]


Let's face it, these days if you're not young, you're old - Red Green grin

#134808 - 12/16/02 02:55 PM Re: Downlights  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Yes, the straw and plaster was the ceiling of the rooms, fitted below the joists.

Good point on the thatched roofs -- I've never had to work in one of those, so I haven't really had to think about it. I can't think of anything in BS7671 that refers to thatched roofs specifically; it would be covered by the general rules.

NM is the American designation meaning Non-Metallic; i.e. equivalent to your TPS or British "Twin & earth." Often known in the U.S. by the name Romex.


#134809 - 12/17/02 01:44 AM Re: Downlights  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,217
SI,New Zealand
Hey thanks Paul, for your explanation of the NM type cable, makes sense, I suppose.
I never knew what Romex was.
Are there any other abbreviations that I should know about, relating to cable types?.
[Linked Image]


Let's face it, these days if you're not young, you're old - Red Green grin

#134810 - 12/17/02 08:57 AM Re: Downlights  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,399
Vienna, Austria
NYM is the german/austrian name for round Romex style cable, followed by number and size of conductors, e.g. NYM 3x1.5, the most commonly used cable type for any wiring, the number 3 means it's a blue conductor for neutral, black or brown for live and yellow/green for ground. Other common types are NYM 3x2.5 and NYM 5x2.5, NYM 4x1.5 is used for a 3way switch (common, 2 travelers and ground).


#134811 - 12/17/02 11:55 AM Re: Downlights  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
There is a whole range of American designations which are completely different from those used in the U.K. and Europe.

SPT-1 and SPT-2 are flat "zip-cord" or "figure-8" power cords, for example. You'll see SO, SJT, and SVT used to refer to some other jacketed power cords in thermoplastic or rubber.

THHN or THWN are PVC-insulated wires such as are commonly drawn through conduit.

Somewhere, I have a list of how to decode all the letters, but I can't lay my hands on it at the moment. One of our American friends might be able to oblige...... [Linked Image]


#134812 - 12/17/02 03:30 PM Re: Downlights  
SvenNYC  Offline
Member
Joined: Aug 2002
Posts: 1,691
New York City
The ones I know offhand because I use them practically every day:

SPT-1, SPT-2 and SPT-3: Single Parallel Thermolastic - the number refers to the thickness of the isulation - 1 is the thinnest.

SPT-1 is usually for 18 AWG wire. SPT-2 can be used for either 18 or 16AWG wire. SPT-3 is usually for flat 3-conductor (2 plus earth) cord such as used on air conditioners.

This is also affectionally known as ZIP CORD, so when you see me use that term, this is what I'm talking about.

* A variation of SPT cord is NISPT - Non Integral Single Parallel Thermoplastic which is double insulated like the two-conductor flat European cord. This has only been on the American OEM market for a couple of years. Haven't seen it on the racks at hardware stores yet....it's usually used for the factory supplied cord for radios, TV sets and tape recorders and other such non-grounded audio/video equipment.

----
SJ: Service Junior

SJT: Service Junior Thermoplastic

* Both of these are double insulated with a round cross section. I believe SJ is rubber jacketed and SJT is thermoplastic jacketed. They are also filled with fiber and paper to strengthen it.
---

SVT: Service Vacuum Thermoplastic - extra flexible for use on vacuum cleaners, has a round cross section also.

---

HPN: Heater Parallel Neoprene (for flat-irons, electric fires, electric toasters, etc.)

--
XT: Christmas (think X-mas) Tree thermopastic - used for christmas tree wires

I just now found the list of all the UL cable designations for AC cords - it even has the insulation dimensions for the different SPT cords:

Go to this link!! [Linked Image]
http://www.volexpowercords.com/technical_information/ul_cord_type_designations.html

In fact, this link has other interesting technical documentation:
http://www.volexpowercords.com/technical_information/

Both links are from Volex, a manufacturer of cordsets.

[This message has been edited by SvenNYC (edited 12-17-2002).]


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