Max Wattage on a Circuit with Newer Bulbs

[larryny]

An electrician once told me that I should always be careful not to exceed too much wattage on each circuit in a house by replacing light bulbs with brighter ones that are of higher wattage (e.g. don't replace all 60W bulbs with 75W or 100W bulbs).

However, with the newer CFL and LED replacement bulbs, not only do the bulbs labeled of the same replacement wattage (e.g. 60W or 75W) have lower lumen output, they actually (in small print on the box) claim to actually use a lot less power (e.g. 60W replacement LED bulbs I just bought claim to only use 9.5W). I'm curious, then. If old traditional 60W bulbs that gave off 1000 lumens each need replacement, can I replace them with 75W 1100 lumen LEDs that claim to use only 13W or 100W LEDs that claim to use only 18W ... without fear of overloading the circuit?

In other words, which "power" rating do I go by to determine whether I am putting the right replacement bulb in ... the "replacement wattage" (i.e. 60W) or the "fine print" wattage of the new bulb (i.e. the 9.5W for a 60W bulb)? Which is the actual power that the bulb is driving the current that the bulb is drawing from the circuit?

Many thanks in advance for your help!

 

[James]

Each lighting circuit is good for up to 1500w of load (15 x 100w traditional light bulbs)

with led replacements, it is impossible to overload a lighting circuit.

 

[littlespark]

The lumens is the light output…. How bright it is.

On LED, the “equivalent” wattage is how bright it is compared to an older filament type lamp

Obviously a 7.5W LED takes a tenth of the power that a 75W does. But LEDs have what is known as “in rush current” which can be many times the running, stated current.
(If there are a lot of lamps switched on at once, it can trip a circuit breaker as an overload if the breaker size was decided on the given wattage)

CFL is now old technology. Compact fluorescent light. Takes a while to get to full brightness compared with LED.

Downside to LED and CFL is the difficulties in having them with a dimmer switch.

 

[Jim_e_Jib]

An electrician once told me that I should always be careful not to exceed too much wattage on each circuit in a house by replacing light bulbs with brighter ones that are of higher wattage (e.g. don't replace all 60W bulbs with 75W or 100W bulbs).

However, with the newer CFL and LED replacement bulbs, not only do the bulbs labeled of the same replacement wattage (e.g. 60W or 75W) have lower lumen output, they actually (in small print on the box) claim to actually use a lot less power (e.g. 60W replacement LED bulbs I just bought claim to only use 9.5W). I'm curious, then. If old traditional 60W bulbs that gave off 1000 lumens each need replacement, can I replace them with 75W 1100 lumen LEDs that claim to use only 13W or 100W LEDs that claim to use only 18W ... without fear of overloading the circuit?

In other words, which "power" rating do I go by to determine whether I am putting the right replacement bulb in ... the "replacement wattage" (i.e. 60W) or the "fine print" wattage of the new bulb (i.e. the 9.5W for a 60W bulb)? Which is the actual power that the bulb is driving the current that the bulb is drawing from the circuit?

Many thanks in advance for your help!

With LED lamps, the actual power used will be the lower of the two numbers you mention. LED lamps convert the electrical energy to light more efficiently than incandescent lamps, which generate a lot of heat as a byproduct.

It's worth noting that LED lamps tend not to match the 'quality' of light from an incandescent lamp. If colour rendering is important to you, it's looking for lamps with a high Colour Renditioning Index (CRI). A typical LED lamp will have CRI of 80 (out of 100). Something abovea CRI of 90 will be closer to an incandescent lamp. You will however get less light output per watt.

It's also worth bearing in mind colour temperature when you're buying LED. Filament based incandescent lamps emit a very 'warm' light of around 2700K. LEDs are available in a range of colour temperatures. The higher the number, the 'cooler' (more blue) the light will be.

I'm not sure how manufacturers measure the light output and equate it to a wattage of an incandescent lamp but I never find it quite matches and always use an LED lamp one 'step' up from the incandescent equivalent stated.

As already said above, in a domestic setting you'll never exceed the capacity of a typical lighting circuit when using LED lamps.

There is a slight risk of the inrush current, when switching on multiple LED lamps, tripping the MCB, but this is unlikely to be a problem in most houses.

 

[pc1966]

Each lighting circuit is good for up to 1500w of load (15 x 100w traditional light bulbs)

1300W surely for 6A & 230V?

Certainly the old design assumption was 100W at every lamp socket, so sizing up how many (usually) 6A circuits would be based on that. But often the division of circuits was done per-floor to minimise fault/maintenance inconvenience, rather than due to hitting the limit in most normal house sizes.

with led replacements, it is impossible to overload a lighting circuit.

Agreed.

As @Jim_e_Jib says in an office or commercial setting when large numbers of lamps are simultaneously switched you can hit a limit due to inrush current (as filament lamps also had), in a domestic setting you won't see that.

 

[DefyG]

On a recent EICR, there were 37 light fittings on one circuit, over 30 of which were 5w LED and not all switched together so overload or inrush were not considered a problem (and hadn't been since installed over 4 years ago)!
Total load was less than 300w if/when all on.

 

[Ian Malone]

An electrician once told me that I should always be careful not to exceed too much wattage on each circuit in a house by replacing light bulbs with brighter ones that are of higher wattage (e.g. don't replace all 60W bulbs with 75W or 100W bulbs).

However, with the newer CFL and LED replacement bulbs, not only do the bulbs labeled of the same replacement wattage (e.g. 60W or 75W) have lower lumen output, they actually (in small print on the box) claim to actually use a lot less power (e.g. 60W replacement LED bulbs I just bought claim to only use 9.5W). I'm curious, then. If old traditional 60W bulbs that gave off 1000 lumens each need replacement, can I replace them with 75W 1100 lumen LEDs that claim to use only 13W or 100W LEDs that claim to use only 18W ... without fear of overloading the circuit?

In other words, which "power" rating do I go by to determine whether I am putting the right replacement bulb in ... the "replacement wattage" (i.e. 60W) or the "fine print" wattage of the new bulb (i.e. the 9.5W for a 60W bulb)? Which is the actual power that the bulb is driving the current that the bulb is drawing from the circuit?

Many thanks in advance for your help!

An electric light bulb is just a basic load , ie 100w equals an element that draws 100w . Lamp fittings for years were designed to accommodate these lamps . Labels were fitted to fittings due to heat generated by lamps . So fittings can be seen with various ratings, eg 20W max , 40W max, etc. The load was purely resistive.
Today these ratings mean little, retro fitting and damage go hand in hand.
A 20W Led light bulb replacement , for example might claim to replace a 100W lamp, but it is not a resistive load, heat is generated at the lamp holder not at the element, and it draws more than the 20W as this the described output.
Theres no easy answer as , the heat output at the lamp holder can vary enormously dependant on brand , style etc of both the lamp and fitting.