The crucial difference was not in fact the lamp wattage but the lamp VOLTAGE. The nearly universal starter was for tubes with a lamp voltage of up to about 120 volts, which in practice meant all common types of lamp up to and including 5 feet in length.

The six foot and eight foot lamps had a running voltage in excess of 120 volts and required the higher voltage starter. These starters were more costly to manufacture, and would in fact start the smaller lamps also, but such use was rather a waste as the starters were more expensive than needed.

Older stocks of the more common lamp starter were marked 4w/80watts, this was misleading as  they would not reliably start a 6 foot 75 watt lamp. The marking was historical from when 6 foot lamps were rated at 85 watts.

It would have been more accurate to mark the cheaper and very common starters "for all standard types of tube up to five feet in length" and to mark the higher voltage starters "for six foot and eight foot lamps"


There were also a third type of fluorescent lamp starter for lamps with a much lower operating voltage of up to about 75 volts. These were intended for operation of a 4 watt up to a 22 watt  lamp on a 110/120 volt supply, or for operation of two such lamps in series from a 220/240 volt supply.

The use of these lower voltage starters was also recommended, but not required, for a single small lamp on a 220/240 volt circuit.


Many suppliers of fluorescent lamp starters followed the same colour code for markings on fluorescent lamp starters.

The nearly universal type=blue.

The 6 foot and 8 foot starters=red.

The 110/120 volt starters =green.


Various special types of starter existed in addition, including thermal starters (large 4 pin), glow starters in a 4 pin can intended to replace thermal starters, double glow starters with two starters in a 4 pin can, others for lamps of unusually high rating. None were popular.

The crucial difference was not in fact the lamp wattage but the lamp VOLTAGE. The nearly universal starter was for tubes with a lamp voltage of up to about 120 volts, which in practice meant all common types of lamp up to and including 5 feet in length.

The six foot and eight foot lamps had a running voltage in excess of 120 volts and required the higher voltage starter. These starters were more costly to manufacture, and would in fact start the smaller lamps also, but such use was rather a waste as the starters were more expensive than needed.

Older stocks of the more common lamp starter were marked 4w/80watts, this was misleading as  they would not reliably start a 6 foot 75 watt lamp. The marking was historical from when 6 foot lamps were rated at 85 watts.

It would have been more accurate to mark the cheaper and very common starters "for all standard types of tube up to five feet in length" and to mark the higher voltage starters "for six foot and eight foot lamps"


There were also a third type of fluorescent lamp starter for lamps with a much lower operating voltage of up to about 75 volts. These were intended for operation of a 4 watt up to a 22 watt  lamp on a 110/120 volt supply, or for operation of two such lamps in series from a 220/240 volt supply.

The use of these lower voltage starters was also recommended, but not required, for a single small lamp on a 220/240 volt circuit.


Many suppliers of fluorescent lamp starters followed the same colour code for markings on fluorescent lamp starters.

The nearly universal type=blue.

The 6 foot and 8 foot starters=red.

The 110/120 volt starters =green.


Various special types of starter existed in addition, including thermal starters (large 4 pin), glow starters in a 4 pin can intended to replace thermal starters, double glow starters with two starters in a 4 pin can, others for lamps of unusually high rating. None were popular.