Omission of overload protection for resistive heating elements.

[SUNRAY]

Indeed. Lead pipe (or lead anything else) is certainly worth selling, but when it comes to iron/steel (which is mainly what I had) one almost has to pay people to 'take it off one's hands'!

Kind Regards, John

I changed some cast iron 4" to PVC and tried to sell it at a reclaim yard, I was soon sent packing and at the scrapyard they allowed me to dump it with them. I was told by a builder I was lucky.

 

[JohnW2]

I changed some cast iron 4" to PVC and tried to sell it at a reclaim yard, I was soon sent packing and at the scrapyard they allowed me to dump it with them. I was told by a builder I was lucky.

You were lucky. What I said in my last post has been literally true on some occasions - that when I have tried to offload cast iron at a reclaim yard, they have offered to 'take it off my hands', but only 'for a price' (my money, not theirs ).

Kind Regards, John

 

[SUNRAY]

You were lucky. What I said in my last post has been literally true on some occasions - that when I have tried to offload cast iron at a reclaim yard, they have offered to 'take it off my hands', but only 'for a price' (my money, not theirs ).

Kind Regards, John

The next lot I took to the council tip and simply it went in the 'metal' section.

 

[JohnW2]

The next lot I took to the council tip and simply it went in the 'metal' section.

Even that is becoming iffy around here - our local council tips are now charging for anything other than 'household waste', and their operatives' interpretation of that seems to vary quite widely!

Kind Regards, John

 

[SimonH2]

That does seem to be a very odd way of doing things. Why would you not want a 12" 1kW one? Why would you want a six feet long one?

To me, this looks like they have a large length of standard element, and the power rating you get depends on the length. They may well have a different range based on a different thickness of element.

As implied in what I have just written, I struggle to understand why they would adopt such a design (for the very reason we are discussing). 'Unnecessarily' bringing 'L' and 'N' things close together would not seem a desirable thing to do. What would be a reasonable justification?

Engineering simplicity ?
It's (generally) a lot easier to run a pair of wires to one end of an element, than it is to run one of the wires to a remote end. it's also makes mounting of the element simpler (just push it in through a punched hole and pop a couple of screws in). And for maintenance, that's now done from just one side of the ducting.

 

[SUNRAY]

To me, this looks like they have a large length of standard element, and the power rating you get depends on the length. They may well have a different range based on a different thickness of element.

That's quite right. The great thing with 'the standard ¼" range' is most element manufacturers use it and replacing an air duct heater is usually just a question of measuring it and ordering a replacement 'off the shelf' usually

Engineering simplicity ?
It's (generally) a lot easier to run a pair of wires to one end of an element, than it is to run one of the wires to a remote end. it's also makes mounting of the element simpler (just push it in through a punched hole and pop a couple of screws in). And for maintenance, that's now done from just one side of the ducting.

Yes that's right, it greatly depends on the type of duct, the materials and possibly the biggest influence is the size of the duct.

 

[JohnW2]

Engineering simplicity ? ... It's (generally) a lot easier to run a pair of wires to one end of an element, than it is to run one of the wires to a remote end. it's also makes mounting of the element simpler (just push it in through a punched hole and pop a couple of screws in). And for maintenance, that's now done from just one side of the ducting.

Has this discussion not slid rather a long way from the context of my comment (and, essentially, of this thread) - namely that of (relatively small) elements in domestic ovens?

Kind Regards, John

 

[SUNRAY]

Has this discussion not slid rather a long way from the context of my comment (and, essentially, of this thread) - namely that of (relatively small) elements in domestic ovens?

Kind Regards, John

Does that matter?

 

[JohnW2]

Does that matter?

Well, I would have been less initially confused if the context had not suddenly jumped

Bernard suggested that some domestic ovens had bifilar elements, and I replied saying that I hadn't come across that, and then that didn't really understand why they would adopt such a design (for such a product). Simon then quoted that comment from me and replied, talking about "doing maintenance from just one side of the ducting" - which left me initially somewhat scratching my head as regards what sort of ducting one might find in a domestic oven.

Kind Regards, John

 

[SUNRAY]

Well, I would have been less initially confused if the context had not suddenly jumped

Bernard suggested that some domestic ovens had bifilar elements, and I replied saying that I hadn't come across that, and then that didn't really understand why they would adopt such a design (for such a product). Simon then quoted that comment from me and replied, talking about "doing maintenance from just one side of the ducting" - which left me initially somewhat scratching my head as regards what sort of ducting one might find in a domestic oven.

Kind Regards, John

Well the majority, if not all, of my comments have been about heaters in ducts and the whole of this page was about scrap metal so yes it has all meandered around.

 

[JohnW2]

Well the majority, if not all, of my comments have been about heaters in ducts and the whole of this page was about scrap metal so yes it has all meandered around.

Yes, so I've now seen. However, as I said, Simon quoted (on this page) my comment about domestic ovens and responded with a comment about ducts

Kind Regards, John

 

[SimonH2]

The same applies to ovens - much simpler to have both connections on the same place and one mounting plate that carries both ends of the element.

PS apologies for mixing different subthreads. As you may have noticed, I'm not finding time to come here as often as I like - so some threads have drifted off before I get to reply to an earlier part !

 

[JohnW2]

The same applies to ovens - much simpler to have both connections on the same place and one mounting plate that carries both ends of the element.

I can see an argument, but that doesn't alter my initial comment - that (although my experience is limited) I personally cannot recall having seen such an element in a domestic oven.

I think there are actually swings and roundabouts. For example, I would imagine that having a physically 'two-ended' element probably makes it easier/simpler to arrange things so that the two live connections are 'kept apart'.

PS apologies for mixing different subthreads. As you may have noticed, I'm not finding time to come here as often as I like - so some threads have drifted off before I get to reply to an earlier part !

No problem - it's good to see you whenever you can manage!

Kind Regards, John

 

[EFLImpudence]

The same applies to ovens - much simpler to have both connections on the same place and one mounting plate that carries both ends of the element.

I can see an argument, but that doesn't alter my initial comment - that (although my experience is limited) I personally cannot recall having seen such an element in a domestic oven.

I think you are getting mixed up.

Don't (all?) oven elements have two ends in (roughly) the same place on one mounting plate?

Having a bifilar element would be pointless; the other end would still have to be supported, presumably by the mounting plate.

 

[JohnW2]

I think you are getting mixed up.

I don't think so - on the contrary, I think we're both essentially saying the same thing, namely ...

Don't (all?) oven elements have two ends in (roughly) the same place on one mounting plate?

Quite ... and, as I said, for what it's worth I cannot recall having seen a domestic oven element which was otherwise - probably not the least because, as you go on to say ...

Having a bifilar element would be pointless; the other end would still have to be supported, presumably by the mounting plate.

Aren't we simply 'agreeing'??

Kind Regards, John