Life of an electrical resistance?

[Christophe]

I wonder what is the lifespan of an electrical resistance?
You will tell me: it depends on the conditions, the maintenance, the type of resistance ... etc etc ...

Yes, but there must be a "life" of "ex-factory" life in the sense of "life expectancy", assuming that the resistor in question is properly used and maintained.

In other words, how many hours of use can we expect the life of an electrical resistance?

[swift2540]

In other words, how many hours of use can we expect the life of an electrical resistance?

Well it depends in the air or in the water?
In water, it depends on the limestone and the "protection" of the resistance ...
Ex: a percolator ...

[Christophe]

Yes it depends ... obviously ...

So let's take some common cases, just to have orders of magnitude:

a) the heating convector ("natural" convection therefore)
b) the fan convector (forced convection)
c) oven resistance
d) the "small" submerged resistance: kettle or percolator
e) the "big" submerged resistance: from the DHW tank or from the washing machine

I say "small" and "big" but the power is often similar, it's just for the bulk.

Here you go!

[swift2540]

Theoretically, I know ... nothing
In practice, I found:
-Electric storage heater (with bricks): lifetime 20 years without problems
In water, here in Liège the hardness is ~ 40 ° F:
-Perco or kettle: ~ 2 years in daily use, with weekly cleaning (vinegar).
- DHW tank with thermoplastic resistance (= like a perco): 3 to 5 years, no more
- DHW tank with soapstone resistance (= in a thermowell): 10 to 15 years on average if the tank is cleaned every 2 to 3 years. After, it is sometimes the tank which holes before the resistance ...

[Christophe]

Ah well 2 years is very little ... Bizarre ...

With us, the percolators and kettles hold a lot longer ... (I think our kettle must be 10 years old but hey we don't use it every day). The last perco we changed was because of "leaks" not resistance ...

By the way, free publicity stunt: it's been 1 year that we use an "instant hot water preparer" from Tefal. It is a kind of small fountain with water heating (or not)

It sucks a lot instantaneously (3000W) but it really only heats the water you need (a cup or less, dosage by hand possible) ... in the kettles there is often a little heated hot water left "for nothing". In addition it's faster ... in 30 seconds you have a hot cup! Ideal for lovers of tea or herbal teas ... But the price is a bit high I find: in the 70 € I think ... it's expensive paid for 1 pump, a resistance and 2 buttons but hey. The novelty is paid and it is very practical. There may be "copies" on the market since ...

Lifespan: no idea but the diaphragm pump is already starting to make a little noise ...

[chatelot16]

good resistance is eternal

depending on the temperature taken by the hot wire

if the resistance is large for a moderate power, the internal temperature is not too high and it is eternal

if the manufacturer has made savings, for the same power it is smaller, so the internal temperature is higher, and it lasts less long

there is also the choice of resistant wire: with ordinary wire you can make an eternal resistance at very low temperature: if the temperature rises it oxidizes too quickly

with special super alloys we can go higher in temperature and remain reliable

[oiseautempete]

Be careful with certain devices (coffee maker, kettle): their heating element is often made of aluminum: do not use vinegar which will quickly eat it and cause leaks ... (the specialized descaler is fine)
For the washing machine, in general vinegar is fine, but beware with French machines (which all come from the same Lyonnaise factory) whose hubs are made of aluminum (a real self-destruct system or I don't know anything about it !): with vinegar it gets eaten very quickly and after that the machine is dead because economically irreparable: I experienced it and I bought a Miele instead ... very expensive but economical in wear and not bothered for 10 years ...

[boubka]

Hello
it mainly depends on the regul and the number of cold starts.
the zero voltage start mode (relay ssr) extends the service life / has a tor mode.

[bernardd]

Concretely, what metals are the heating resistors made of?

The filaments of the incandescent bulbs were made of tungsten for example ...

Another post talked about aluminum.

What are the other compositions?

[chatelot16]

the filaments of the lamps are made of tungsten, which undergoes a very high temperature under vacuum or under inert gas but which is worth nothing in the air: it would oxidize as quickly as wire!

for air resistance it is often nickel based alloy

the stainless steel wire for mig welding of stainless steel makes me good wire for resistance ...